The K2 Spyre 100 Heat SV is an all-mountain ski boot designed to give intermediate to advanced skiers a reliable blend of comfort and performance. Built to handle everything from groomed runs to variable snow conditions, it’s aimed at anyone looking for a responsive yet forgiving fit on the slopes.
With a 100 mm last width, the Spyre 100 Heat SV offers a medium fit that strikes a balance between comfort and edge control. Its flex index of 100 provides enough stiffness to transfer energy efficiently during turns without feeling overly rigid, while the mid-volume shell accommodates a range of foot shapes without excess space.
The term “last” refers to the width of the boot’s forefoot area; at 100 mm, it sits in the middle of the spectrum, offering room for most feet without sacrificing precision. The flex index measures how much resistance the boot gives when you lean forward—a 100 flex is suitable for skiers who need solid responsiveness underfoot. “Mid volume” indicates moderate internal space, helping to ensure a snug, supportive hold without hot spots or pinching.
Continue reading