Hope Pro 4 Rear Disc Hub 32H QR 135mm Black XD Equipped with stainless steel bearings Taller Flanges than the Pro 2 Additional end caps sold separately Convertible to 10mm Thru Bolt x 135mm, 12mm Thru Axle x 135mm, and 12mm Thru Axle x 142mm with tool-free end caps Upgraded 44T ratchet ring and 4-pawl drive system for quicker engagement