The 2021 mens Descente i4 SIO Insulated Jacket is a strikingly stylish regular fit jacket. This technical jacket is a comfortable 4 way stretch fabric and is 20K waterproof and breathable. This jacket has the Boa system which is a simple closure system that can be adjusted quickly to provide maximum comfort with one turn of the dial. The jacket is insulated and also has the Descente Heat Navi system which converts infrared rays from the sunlight into stored heat even in adverse conditions. SIO minimum pattern cutting means fewer parts so fewer seams and better waterproofing and greater freedom to move.