![IsoPro Canister](http://thebearmountain.com/cdn/shop/products/1481-6021-0-image_640x640.jpg?v=1608152587)
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.