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.

• Three Sizes: 
• Improved Performance: 80/20 blend of isobutane and propane delivers superior performance throughout the life of the canister and in colder temperatures.

• Clean-Burning: Zero-maintenance combustion.
• Fuel Gauge: Built-in float gauge determines how much fuel is left (4 oz. and 8 oz. canisters).
• Recyclable: Consult your local recycling center for regulations.