What are your NSN's?

You can find Revision Military's complete list of National Stock Numbers (NSN) here.

Do you offer a Military or Law Enforcement discount on your Eyewear products?

We are proud to offer a 30% discount to military and law enforcement personnel on all eyewear products.  We are happy to also offer a discount on our Batlskin products, but please call customer service for this information. You can order directly through our website or by contacting customer service at 1-800-383-6049.  If you plan to order online, please contact us for a discount code at customercare@revisionmilitary.com. Please note discount codes are valid for singular purchases. Group or unit discounts are not available online.

How can I become one of your dealers?

Please e-mail customercare@revisionmilitary.com and we will forward your request to the appropriate person within our organization.

Are you hiring?

We are always looking for talented people to grow with us, especially in the areas of administration, science and technology, engineering and manufacturing. If you are interested in exploring opportunities at Revision, please send your resume and a cover letter by e-mail to careers@revisionmilitary.com.

Requesting a catalog?

A copy of our full catalog can be viewed online by clicking here.

Who do I contact regarding T&E?

Please contact Ron van Zuilen, International Sales Support Manager, at rvanzuilen@revisionmilitary.com.

Requesting a donation?

Please contact Kelly Goudy, Marketing Events Manager, at kgoudy@revisionmilitary.com.

Who do I contact regarding Media Ad Placements?

Please contact media@revisionmilitary.com.

Who do I contact regarding Public Relations opportunities?

Please contact media@revisionmilitary.com.



What is your return policy on eyewear?

We are happy to accept returns up to 30 days after the date of purchase. If you order a pair of eyewear and find that they are not quite what you’re looking for, simply give us a call at 1-800-383-6049 and we’ll be happy to help you set up a return. We can either issue you a refund on the original form of payment, or issue a credit towards another pair of eyewear. A $9.95 USD shipping charge applies to all exchanges.

Is there a warranty on your eyewear?

All of our eyewear is covered under a 3 year manufacturer's warranty. Click here for warranty. If you would like to file a warranty claim please e-mail customercare@revisionmilitary.com or contact us toll free at 1-800-383-6049.

Are scratched lenses covered under the warranty?

Scratched lenses are not covered under our manufactures warranty. Replacement lenses for our Sawfly Eyewear System, Desert Locust Goggle, Wolfspider Goggle, Stingerhawk Spectacle and Bullet Ant Tactical Goggle can be purchased from our website, www.revisionmilitary.com or by calling us toll free at 1-800-383-6049.



What are the dimensions of the Hellfly Ballistic Sunglasses?

Our Hellfly Ballistic Sunglasses are 135 mm wide (temple to temple). Each lens is approximately 65 mm wide and 35 mm tall. The nosepiece at its widest point is 25 mm and at the narrowest point it is 10 mm wide. The nosepiece on the Hellfly is adjustable, making it easier to fit on the bridge of your nose comfortably. If you do find that they don't fit, we would be happy to issue a 100% refund within 30 days of purchase.

How do I know what size Sawfly I need?

Our Sawfly Eyewear System comes in sizes small, regular and large. We recommend the size small to people who have a hat size between 6 1/2 and 6 7/8. The regular is recommended for people who have a hat size between 6 3/4 and 7 3/8 and the large is recommended for people with a hat size between 7 1/4 and 7 1/2. To view our Sawfly Sizing Guideline click here.

How do I know what size Sawfly I own?

Backed by a 3 year limited warranty, Revision products are built to last. Should however, you require replacements parts or accessories for your Sawfly Eyewear System, you will need to know what size you own. You can also determine the correct size by looking at the lens itself. Here's how:

Remove the nosepiece from the lens. Look at the area where the nosepiece fits.

On the regular size Sawfly there are two sets of notches - like a Christmas tree.

On the large size Sawfly there is only one set of notches.

There are also markings on each lens to determine if it’s a regular or small lens. The small Sawfly Lens has an “+SH” on the inside of the lens above the nosepiece. The regular has only “+S”.

Will a Sawfly regular size lens fit into a large Sawfly frame?

The Sawfly small and regular size lenses are only compatible with the regular size Sawfly frame. The size large lenses are only compatible with the size large frame.



How much does shipping cost?

FedEx ground rates for shipping in the United States vary depending on geographic location. The flat rate to ship to Canada is $27.60 USD, via FedEx International Economy Services. International shipping costs will vary depending on location.

How do I purchase your products?

To find out how to purchase Revision eyewear, please visit our on-line store at http://www.revisionmilitary.com//store/.

Are your Eyewear products available to the public or just military and government agencies?

Though our eyewear is purpose built for military use, our products are available to anyone who requires superior eye protection. This includes the general public, active and retired military, tactical/law enforcement users, and sports enthusiasts alike. We work with many dealers across the country and internationally who cater to our various markets. To find out how and where to buy, please visit our Find a Store page. You may also buy direct from Revision online.

Do you ship to APO/FPO addresses?

Yes. We ship eyewear products ordered via the Revision on-line store to APO/FPO addresses by way of United States Postal Service "Priority Mail". We estimate 5 to 14 days for delivery once the order has been shipped however, some destinations may take longer.



What are the key attributes to the new Stingerhawk Spectacle?

Designed to complement a variety of Armed Forces' helmets, the Revision StingerHawk, an ultra-lightweight spectacle features a compact, low-profile design that delivers on comfort without compromising performance. It features a lightweight, sleek wrap-around style that says powerful and aggressive. The lenses are made of indestructible, optical grade polycarbonate that can be interchanged quickly for various light conditions and provide 100% protection from harmful UV-A, UV-B and UV-C rays. It is compatible with the Revision Rx Insert when used with the StingerHawk Rx nosepiece. The lenses exceed military ballistic impact requirements for spectacles and goggles.

Are polarized or photochromic lenses available in any other products besides the Sawfly Spectacle and Hellfly Ballistic Sunglasses?

At this time, the polarized and photochromic lenses are only available with the Sawfly Eyewear System and Hellfly Ballistic Sunglasses. For additional product lines and accessories, there are no immediate dates as to when these options may be available. Please check our website for the most up to date product offerings.

What if I need to replace my nose piece on my Hellfly Ballistic Sunglasses?

We are happy to replace the nose piece on your Hellfly Ballistic Sunglasses. Please email customercare@revisionmilitary.com and provide us with a mailing address and we’ll get a new nose piece shipped to you right away.

Is the Desert Locust Thermal Lens compatible with the Desert Locust Goggle System or just the Desert Locust Extreme Weather Goggle System?

The Desert Locust Thermal Lens is fully compatible with the Desert Locust Goggle, Asian Locust Goggle and Desert Locust Fan Goggle.

Can I purchase the fan separately for my Desert Locust Goggles?

The Desert Locust Fan Goggle is sold as a complete system. The fan cannot be purchased separately as an add-on to the Desert Locust Goggle.

What is the difference between the newer Wolfspider Goggle and the previous version?

The new low profile Wolfspider Goggle has been redesigned for a better, more comfortable fit, and it is now prescription capable, fitting with the Revision Rx insert. The previous version Wolfspider components, such as the lenses, will not be compatible with the newer style goggle.

Is there anything I can do to prevent my lenses from fogging?

Revision lenses are manufactured with a coating that helps fight both fogging and scratching. However, another great tool is our Anti-Fog Cloths. The Revision Anti-Fog Cloths use advanced nanotechnology to help keep the lenses from fogging up. They are sold in a carton of 3 on our website and each cloth can be re-used up to 25 times.

What is the best way to clean my lenses?

Besides using our lens cleaner, we also recommend using a diluted solution of warm water and dish soap. Wash, rinse and let air dry.



With which helmets do the Batlskin components work?

The Batlskin Viper components have been designed to work with two specific helmets: 1) Standard issue ACH helmets and 2) Revision Viper A1 (Aramid) and Viper P2 (composite) helmets. The Batlskin Cobra components have been designed to fit the Revision Cobra P2 (composite) helmets.

Currently, the Batlskin components (front mounts, rails, visors, and mandible guards) are available for all four size helmets, S, M, L, and XL.

Is the Batlskin Helmet Line available to the military? Law enforcement?

Yes. The Batlskin Helmet Line is available for military and law enforcement unit level buys. It is also available for individual military/law enforcement purchase through the Revision online store.

Is Batlskin Helmet Line available for civilian purchase?

At this time the Batlskin helmet accessories (front mount, visor, rails and mandible guards) are available for civilian purchase.

What is the warranty policy for the Batlskin product line?

Revision warrants all products sold by Revision to be free of defects in material and workmanship for seven years after the date of the first sale for helmet shells; three years after the date of the first sale for non consumable helmet components such as fit band, hardware, and buckles; and one year after the date of first sale on all other products, including consumable components such as comfort layer, impact pads, and retention system. This warranty is only extended to the original purchaser. If a product is found to be defective by Revision, in its sole discretion, Revision's only responsibility shall be limited to repair or replacement of the defective product. Revision will not be responsible for any costs, losses or damages incurred as a result of loss or use of product. The warranty is subject to some limitations and the details can be found on the following document. Click here for warranty

Does the Batlskin Head Protection System protect against blunt force, blast and ballistic trauma?

Yes. In order to help reduce brain injuries, the Batlskin Head Protection System has been designed not only to mitigate ballistic threats, but also to protect against blast waves, deflecting energy around the system. With regards to ballistics, the High-Threat Mandible Guard offers the same level of protection as the ACH helmet. As injury models include both ballistic and non-ballistic injuries, the Batlskin Head Protection System provides protection against blunt impacts to the face and jaw caused by collision with vehicle interiors and weapons.

What is the balance between fragmentation protection and weight?

Together, the Front Mount and Mandible Guard weigh only 1 pound and provide the same level of protection as the ACH helmet. This trade off of weight versus protection is commensurate with U.S. Army ballistic requirements and the operational reality of today's battlefield.

Is the Batlskin Head Protection System compatible with NVGs?

Yes. The Batlskin Front Mount receiver component accommodates the Batlskin Viper Visor as well as widely used NVGs, such as the PVS-7 and PVS-14. If using other types of NVGs, such as ENVG III NVGs, the receiver component can be swapped for the upgradable receiver that is included with these NVGs. When NVGs are worn, we recommend using clear ballistic eye protection such as the Sawfly. Watch the Video

Are the ARC rails compatible with Revision helmets?

Revision's High Cut Helmets accommodate the Batlskin Interlocking and Standalone Long Rails that allow for easy installation of cameras, flashlight, and other head borne accessories onto helmets. Revision also has designed a rail-ready cut of the ACH-shaped helmet that is meant to work with current ARC rail systems available upon request. Please contact Customer Service at customercare@revisionmilitary.com.

How do you use weapons with the Batlskin Head Protection System? Can you achieve a proper cheek weld while sighting weapons? If not, how do you overcome this?

The Batlskin Head Protection System is intended to be used with current weapon optics. Most standard red dot, holographic sights and scopes are capable of being used with this system. For use during limited visibility operations, standard IR lasers can be utilized without a cheek-to-stock weld. As a contingency, the ballistic mandible is easily removed for use with traditional iron sights. Watch the Video

What kind of field-of-view is possible when wearing the Batlskin Head Protection System?

The optically correct ballistic Visor provides the same field-of-view as the ACH helmet and is manufactured to ensure distortion-free vision across the whole panoramic surface of the lens. When the Mandible Guard is in use, inferior (lower) field-of-view is comparable to that of ballistic goggles. If additional field-of-view is required, the Mandible Guard can be easily removed.

Can the M50 gas mask be worn with the Batlskin Head Protection System?

When wearing an ACH helmet fitted with Revision’s Front Mount, it is possible to wear the M50 CBRN mask with the Visor closed. The Mandible Guard is not designed to be worn with the CBRN mask in use. Watch the Video

When wearing the Batlskin Head Protection System, how easily can you communicate with others; are face-to-face conversations clear? Is communication with communications gear possible?

The Batlskin Head Protection System has been specifically designed for use with over-the-ear communication headsets. The Mandible Guard provides sufficient clearance for communication headsets, boom microphones as well as the headset earpiece. The Mandible Guard can be tilted downwards by varying degrees allowing for improved sight capabilities, eating, and drinking.

How breathable is this system?

The bottom of the Mandible Guard is all open, unlike a gas mask, which allows for proper ventilation.  In severe environments, the Visor can be articulated to the ‘vent’ position to increase ventilation. Additionally, the Ballistic Visor has an anti-fog coating, similar to ballistic goggles issued for today's military.

How hot does the system get?

The Batlskin Head Protection System was designed with thermal mitigation in mind. Each component of the system is modular, allowing for wear in varying threat environments. The Visor's ‘up’ and ‘vent’ positions allow for the dissipation of heat. For extra ventilation, you can also wear the Visor without the Mandible Guard.

When wearing the Batlskin Head Protection System, will the visor fog?

The Ballistic Visor has an anti-fog coating on the inside of the lens, similar to ballistic goggles issued for today's military. In severe environments, the Visor can be articulated to the ‘vent’ position to further reduce fogging. In an emergency, the Ballistic Visor can be removed in seconds should an obscurant prevent the proper field-of-view. Watch the Video



What is the difference between the Rx carrier and the StingerHawk Rx carrier?

The Rx carrier is compatible with the Sawfly and StingerHawk Eyewear Systems, and the Desert Locust, Asian Locust, and Bullet Ant Goggles. However, the StingerHawk Eyewear System requires a specific Rx carrier nosepiece. The StingerHawk Prescription Rx Carrier Kit includes a carrier and two Rx nosepieces (clear and black).

What are your prescription options, and what are their limitations?

The Rx Carrier can accommodate a single vision prescription that is +11 through -11, and is compatible with our Sawfly Spectacle, StingerHawk Spectacle, Desert Locust Goggle, Bullet Ant Goggle, and Wolfspider Goggle. The Hellfly Ballistic Sunglasses can accommodate a single vision prescription that is +1 through -4.

How do I fill my Rx Carrier with my prescription?

We suggest the following 3 options:

  1. Have your prescription filled by any licensed optician. To do this you will need to purchase one of the Rx Carrier Kits from one of our licensed dealers or directly through Revision, and take the frame to your optician for fulfillment.
  2. Have your prescription filled by Revision. Simply complete the Rx Fulfillment Form and fax it back to us. The $99.99 USD flat rate includes the prescription & Carrier. It takes approximately 2 weeks from the time we receive your order until it is shipped.
  3. If you are active military, please visit your on-base optometry clinic, where you can obtain a filled Rx Carrier through the SERTS Program. Active, Reserve, and National Guard members can also have their prescription filled for free through the Naval Ophthalmic Support & Training Activity (NOSTRA). http://www.med.navy.mil/sites/nostra/Pages/default.aspx

Are you able to fill a bifocal prescription?

We are unable to fill a bifocal lens as you would need to be onsite for the measurements that these prescriptions require. We are able to fill a single vision prescription only. You can certainly purchase the blank prescription carrier frame and bring it to your local optometrist where they can take your measurements and fill your bifocal lens prescription on site. The cost to purchase the blank prescription carrier would be $24.99 USD (+S/H). This can be purchased directly from our website, www.revisionmilitary.com, or by contacting customer service toll free at 1-800-383-6049.

What is the difference between the APEL Rx carrier and the 2011 Rx carrier?

The 2011 Rx carrier is optimized for a more universal fit. Both carriers are compatible with the Sawfly Eyewear System, StingerHawk Eyewear System, Desert Locust Goggle, Asian Locust Goggle and Bullet Ant Tactical Goggle. Additionally, the 2011 Rx Carrier does not require a “correction factor” when being filled by an optometrist.

Can I wear your eyewear over my eyeglasses?

We recommend that you do NOT wear eyeglasses under your Revision Eyepro. We go to great lengths to ensure the ballistic capabilities of our eyewear. Wearing regular eyeglasses under your Revision eyewear puts your safety at risk. Because, while Revision frames and lenses are able to withstand ballistic impact, your regular eyeglasses very probably cannot, and could shatter, potentially causing serious eye injury, blindness or even death.   Please see the information above regarding our Revision prescription options.

Does the military or law enforcement discount apply to prescriptions?

We do offer a discounted price on our Rx carriers to military and law enforcement personnel. The discounted price is $49.99 USD (+$9.95 S&H).  We also offer discounted prices on the Hellfly prescriptions, but those vary depending on which lens/frame combination you purchase. When filling out the Rx order form, please make a note anywhere on the form that you would like to take advantage of the military/LE discount and we will be sure to apply it to your order.

Does the $99.99 cost to fill the carrier include the carrier itself or is that additional?

The $99.99 USD cost includes the prescription lenses as well as the Rx carrier vision correction system itself. You will receive your order with the lenses already in the carrier.



Will the SoloPack and SharePack function underwater? If so, up to what depth?

The SoloPack and SharePack are designed to meet the MIL-STD-810G Immersion - Method 512.6 Procedure I which is meant for equipment that might get inadvertently immersed (i.e. dropped in a stream by accident) but are not currently designed to operate underwater. Should a sealed power solution be of interest, please email customercare@revisionmilitary.com. Please note that underwater operation requires a different class of connectors (not NettWarrior compatible) and a significantly bulkier design to protect from water damage.

Can I take these batteries on a commercial airline?

Yes, however various restrictions apply depending on the airline. Pending the UN/DOT 38.3 Safety Certification, the SoloPack (96 Wh) will be authorized for commercial flights. The SharePack (150Wh) is above the typical regulatory limit of 100Wh and may not be authorized for commercial flights with some airlines. Regulations regarding lithium ion batteries vary depending on commercial airlines. For guidance on commercial airline battery restrictions please click here. It is incumbent upon travelers to verify with airlines whether restrictions have changed prior to boarding, and seek approval for carrying lithium batteries in their carry-on luggage. Note that placing the rubber plug provided into the SoloPack or SharePack connectors meets airlines’ short-circuit requirements for taking Revision’s batteries onboard an aircraft.

What kind of charger should I use to charge the SoloPack and SharePack?

Any SMBus charger should be used to charge the SoloPack and SharePack rapidly and most efficiently. Some examples include Desktop Evaluation Charger (6130-01-542-5108) and Soldier Charger (6130-01-545-1983). The SharePack can, however, be recharged from any energy source. A full comprehensive list can be found in the respective user guides.

What are the dimensions of the SoloPack and SharePack?

The dimensions of the SoloPack battery are: 181x77x30mm (LxWxH). The dimensions of the SharePack Power Management System are: 190x165x28mm (LxWxH).

How often should I recharge my SoloPack and SharePack?

The batteries should be recharged after each use to prolong life. Unlike the internal chemistry of other battery types, lithium ion batteries will never 'crystallize' or develop a 'memory'. They can be recharged at any state-of-charge and will only show signs of lost capacity after several thousand cycles.

How heavy is the SoloPack and SharePack?

Both the SoloPack and SharePack are lightweight, with the SoloPack weighing 550g (approx. 1.2 lbs) and the SharePack weighing 1125g (approx. 2.5 lbs).

Does the SoloPack and SharePack come with a case?

Yes, both the SoloPack and SharePack come with a custom carrying case that attaches to a user's vest.

How do I go about replacing a battery should it be defective?

Please consult our warranty for details.

How should I store these batteries?

The batteries should be stored at 50% state-of-charge, placed into shutdown mode (no equipment or cables connected), and at an ambient temperature of 25°C. The shelf life under these conditions is 3 years. Please note that the SharePack will need occasional recharging back up to 50%.

Do you have pricing for batteries and cables?

Please visit our online store for pricing and purchasing.

How many SharePacks can I string together and what power can it emit?

A network of SharePacks can support up to 8 in a configuration, whether in star topology or as a daisy chained hub. In a star topology (parallel) you could theoretically emit 800W (8*2*50 = 800W) of power. In a daisy-chain topology (series) you are limited to emitting 50W on your output port, however multiply the duration of your power emission 8 fold.

How many SharePacks can I update at once?

There is no limit to the number of SharePacks that can be updated at the same time; as many as you have USB ports to support. The software will recognize these connected devices and update them one after the other.

What happens if the USB cable is disconnected while updating the SharePack's firmware?

It is crucial that the user responsible for updating the device ensures that it is properly connected to the PC and that once updating commences, the cable does not become disconnected. Disconnecting a cable during an update may render the SharePack unusable, requiring the battery to be returned to Revision for servicing.

How do I update the SharePack's firwmare?

The SharePack supports in-field software updates through a connection to a PC via USB. A host interface application designed and developed to be an intuitive and self-explanatory product is used to execute the SharePack field firmware updates. For instructions, please refer to your SharePack user guide.

Are there any regulations for shipping these batteries?

Yes. The required certification for shipping the SharePack and SoloPack as per UN/DOT 38.3 is pending. Until certification is complete, the batteries are classified by default as Class 9 Dangerous Goods and shipping has to abide by specific rules. For guidance, refer to http://www.tc.gc.ca/eng/tdg/faq-319.htm.

How will I know if my battery is dead?

A 'Servicing Required' error message will appear, indicating that the SharePack should be returned to the manufacturer for servicing.

What happens if I use my battery outside of the operating temperature range?

The SoloPack and SharePack will disable charging and discharging through the battery cell stack when the internal temperature reaches 70°C ± 5°C. It will resume normal operation when the internal temperature reaches 50°C ± 5°C. Charging and discharging through the battery cell stack will be permanently disabled should the internal temperature exceed 93°C ± 5°C.

Do you have 90º connectors?

Revision does not currently offer 90º connectors, however Revision can explore sourcing such connectors should there be a demand.

How do I get set up my battery to work with my piece of equipment?

Please refer to the accompanying instruction manual for step-by-step instructions on how to connect your equipment to your SoloPack and SharePack. Instruction manuals can also be accessed by scanning the code on the back of your battery using a smartphone device.

What equipment will my battery work with?

Nerv Centr products have been designed to work with a wide range of currently fielded equipment. For additional information, please email power@revisionmilitary.com. Associated accessories required to power your equipment can be found here.

How long will my battery last?

SharePack is rated for 150Wh and SoloPack for 100Wh. The amount of runtime depends largely on what and how equipment will be used. When fully charged, if powering equipment that draws one watt continuously, you can expect to get 150 hours (6.6 days) of runtime from SharePack, and 100 hour (4.4 days) with SoloPack. Most handheld radios will require 2-3 watts when not transmitting. This means you can expect approximately 2-3 days of runtime (this is reduced when transmitting). Larger radios will require much more power (10-20W) which reduces runtime to a couple of hours. The best indication of runtime is displayed on the SoloPack's state-of-charge display or the SharePack's main screen and this will be your best indication of the duration of battery life.

I have lost my instruction manual. Can I access instructions online?

The instruction manual for the SoloPack and SharePack can be accessed by scanning the code on the back of the battery using your smartphone device.

If the battery is not being used, how frequently do I have to charge it?

If the SharePack will not be used for a week or longer, it must be fully charged and put into shutdown mode. Otherwise, the SharePack will deteriorate and last only a few months as opposed to a few years. Failing to charge and shut down will leave the SharePack consuming a small but continuous amount of current which can drain cells to a point where they cannot recover. If the SoloPack is not being used, simply charge the battery to 50% and leave in an ambient environment. It is recommended to perform maintenance recharges back to 50% at regular intervals, two or three times a year, to maintain the battery in optimal condition. Otherwise its shelf life is approximately 3 years.

How deeply can I discharge the SharePack without failure?

The battery can be depleted down to zero percent. As a safety mechanism, the software will display an 'Apply Charger' message when getting critically low, informing the user to recharge the SharePack. If not accomplished, software will internally shut down the device and only awaken once recharging. This is done to internally protect the lithium ion cells. If left unattended for a month after complete depletion, the lithium ion cells may be permanently damaged and render the SharePack unsalvageable.

How do I dispose of the battery?

Similar to one-time use batteries and cell phone batteries, the SoloPack and SharePack can be disposed of in commonly used battery disposal boxes. Please contact your local battery recycling program to determine your nearest disposal location.

Is there a potential to damage my equipment if I don't set the voltage correctly?

It is important that the ports are set in accordance with the voltage required by the piece of equipment being powered. Otherwise, there is a possibility that the equipment could be damaged. Please pay special attention when setting the voltage.

What is the operating temperature range of Nerv Centr products?

The SoloPack and SharePack are designed to operate in temperatures of -32°C to +55°C.

What is the energy density of the SoloPack and SharePack?

The SoloPack's energy density is 175 Wh/Kg, containing as much power as 64 AA NiCd batteries and offering 4.25 times the energy density. The SharePack's energy density is 135 Wh/Kg, containing as much power as 100 AA NiCd batteries and offering 2.75 times the energy density.

What happens if a SoloPack or SharePack is hit by a round or shrapnel?

Revision’s battery systems offer the same level of safety as other man worn batteries currently in use by the U.S. Military. The SoloPack and SharePack will behave in a similar manner to most standard military batteries such as the BB-2590 or LI-145; they may heat up or, in extreme situations, could conceivably catch fire if hit by a round or shrapnel. Revision continues to investigate operationally safe battery systems.