IsoPro Fuel CanisterDescription Performance boosting fuel for your canister stove. 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 Three