Efest Safety Charging Bag 7 x 9
From the eFest site:
Materials: Fire control explosion-proof materials
Safe Charging Bags, very good in strength of extension, thermostability, antiflamability and safety.
Safe Charging Bags are a flame retardant bag, a convenient way of safeguarding your batteries during charging, transit, and storage.
Simply enclose the batteries in the bag, route your charge wires through the vents at either side of the top flap, and fold the flap closed, sealing with the industrial grade hook and loop fastener.