The breathable, hook-sensitive neoprene vest grips the skin to allow precise placement of the donut-shaped foam pad. The hard-shelled foam pad helps protect the AC joint from further injury. Simply apply adhesive-backed hook to the foam pad to prevent migration. On the inside the perforated, breathable, rubber-like neoprene grips the skin so the support moves with the athlete - it’s as if the stabilization straps are attached directly to the body.