Product Description: MSR IsoPro is a performance-boosting, 80/20 blend of isobutane and propane, with the purest isobutane (5% or less n-butane) of any canister fuel. This clean-burning formulation maintains higher internal pressure at lower temperatures than standard butane/propane mixtures, delivering superior cold weather performance and more consistent output over the life of the canister. Features: Canister is designed for use with all MSR canisters stoves and will work with many other brand canister stoves. 80/20 blend of isobutane and propane is clean burning, delivering superior performance throughout the life of the canister and in colder temperatures. Printed float gauge allows you to place your canister in water to determine how much fuel is left Self-sealing valve allows the canister to be removed from the stove burner for transportation. Canisters can be recycled under specific conditions; consult your local recycling center for regulations