Lipo batteries are notorious for spontaneously self igniting when not cared for properly or charged too quickly after discharging. Made from a fiberglass woven fabric, this lipo sack is fire retardant and we strongly recommend charging your lipo batteries in these bags. Never leave a charging lipo unattended. These are cheap insurance against a possible flameout or fire. This bag is 18x22cm and will hold (3) 2200mah 3S1P packs comfortably, (1) Inspire 1 pack or (2) Phantom batteries.