The Adrenaline Pro S1K GTX BOA Boot is a mountain-focused boot for the most aggressive riders looking for premium warmth, support and comfort. The Adrenaline Pro S1K GTX BOA Boot is modeled after the Adrenaline Pro S GTX BOA Boot, the most popular boot in snowmobiling, and delivers the same high-level performance now with the additional warmth of 1,000G 3M Thinsulate and superior comfort of the OrthoLite O-Therm insole technology, a molded tongue for better support on the running boards as well as stronger BOA dials designed to pop off and reattach rather than break off for longer-lasting adventures.