The RidgeMonkey EcoPower USB Heated Gas Canister Cover is designed to fit all common 440-500 size butane / propane mixture camping gas canisters, the USB-powered heater coil will gently warm your gas canister enabling efficient use of every last drop of fuel even in the coldest conditions. Weather-resistant wipe clean neoprene outer with elasticated spoon strap and zipped lower section. 5V 2A USB input provides extended runtime while remaining compatible with almost all common USB power sources.