EVOLUTION FLEX. PAINTED CUFF. EVEN FIT. The CRANK BOA® snowboard boot returns with a timeless style and stiffer construction. The BOA® H3 lacing system and evolution flex provide super good support for progressive all-mountain performance, while the thermo-ad fit liners with built-in lacing and articulated cuffs provide custom comfort and premium performance to take your boarding skills to the next level.