The KK SP2 is milled out of 7 series aluminium and anodised. It is designed to have two functions. 1: It keeps the tip of your spike 5mm further from the instep of your foot this matches your Spikescender side. It is handy when using short gaffs on a thick barked tree. 2: you can attach your HAAS or foot loop straight to it with a small carabiner, eliminating annoying foot loop issues and minimising the amount of rope needed under a hand ascender or HAAS.