The Adrenaline Pro S GTX BOA® Boot is a mountain-focused boot for the most aggressive riders. Featuring a new custom-developed Michelin® sole for grip and durability, the Adrenaline Pro S GTX BOA® Boot is the most popular boot in snowmobiling and now more supportive. Stronger BOA® dials combine with a molded tongue for improved closure force and lace force distribution, creating added support and comfort on the running boards.