Sinz Elite XXX pro bottom brackets are the ultimate upgrade for any 24-millimeter spindle crankset. You get a killer, high-quality, silky smooth bottom bracket that feature forged and CNC-machined external aluminum cups and are compatible with Sinz Elite XXX, Shimano DXR/Saint and other 24-millimeter spindle cranksets and fit standard English thread (1.37�€� x 24T) 68- and 73-millimeter bottom bracket shells. The Pro model has the added bonus of precision tapered roller bearings. The super-durable bearings will provide longer bottom bracket life even under extreme use. These bearings come as standard on the Sinz Elite XXX Cranks.