The stiffest of K2’s women’s boots, the K2 Spyre 110 Ski Boots are meant for high-speed assaults on the burliest of terrain. K2’s women-specifi c construction, featuring a decreased boot volume, narrower heel and 15-mm lower cuff height, accommodates the shape of a woman’s lower leg. An interlocking mechanism on the spine called Energy Interlock connects the cuff and shell, and allows for a rivetfree design yielding a smoother fl ex. To provide additional support for your high-octane descents, the spine is reinforced with a co-injected, Y-shaped polymer support system, which K2 calls PowerFuse SpYne, to ensure power and response when raging downhill.