This kit can be used to either upgrade or service your DT Swiss star ratchet hub. If you have a DT Swiss star ratchet hub with less engagement like 18t or 24t, this upgrade will give you 36 teeth for higher engagement and a more immediate power transfer. This is a great upgrade as higher engagement allows for an easier time getting up and over tricky, technical climbs, where even losing out on half of a crank rotation might hold you up. If you&';re looking for even more engagement, check out the 54t Upgrade Kit for the highest engagement possible!