The Valken Lipo Battery Charging and Travel Safety Sack provides an added layer of protection and peace of mind while charging your airsoft lithium batteries. These LiPo safety sacks are made from fire resistant glass fiber material, and reduces the chances of damage occurring in the event of a Lipo airsoft battery catching fire. These Lipo battery bags come with a secure heat resistant hook and loop closure, and ensures your battery is protected while charging, or when used for storage. We recommend our Valken Battery Tester when using your lithium airsoft battery.