The Lipo-Guard is a fireproof bag, designed to stop and contain the fire caused by incorrectly or poorly functioning lithium batteries, especially during charging. It is made from a fiberglass woven fabric, similar to fireproof suits worn by firefighters. It is highly recommended to charge your Lithium Ion batteries inside of a LiPo safety bag. Batteries can fail, when they do it normally causes venting and sometimes fire. This bag will prevent flames from escaping and allow for venting so all you see is smoke. Most chargers with a cord like our Trustfire TR-001 Xtar WP2II or the eGo USB chargers will work in this bag. LIPO-GUARD Bag Use Instructions: Insert batteries into charger making sure polarity is correct. Place charger in the bag towards the bottom. Place Li-Po Bag on non-flammable surface. Place the charger leads through the space (left or right seam) at the top of the bag. Close top flap of Li-Po Bag and press, ensuring the seal is secure. Charge battery using proper charging practices. Never leave charging battery unattended.