ATK Titanium “U” Spring With Rolling-In System is a spare part for the heel attachment in your ABK Revolution World Cup and R.C.A World Cup Vertical touring skis! It includes: - 2 titanium "U" springs with Rolling-In System- 2 standard spring retaining screws- 2 new design spring retaining screws ATK Titanium “U” Spring With Rolling-In System spring for ski mountaineering bindings