Made of supreme fire retardant fiberglass nylon. 100% FIRE PROOF GUARANTEED! Stands up against fire and heat up to 1000 ?(550 ?).Do not buy cheap items to risk your family or property. Always remember to comply with li-poly charging and safety guidelines and NEVER leave charging or damaged lipo batteries unattended. This flame retardant bag is a convenient way of safeguarding your LiPo batteries during charging, transit, and storage. As we adopted fiberglass in synthetic materials, there would be a few splinters on its surface. We recommend you to use the handle when carrying this bag in order to reduce discomfort.