The PF30 standard is widely used. To make it compatible with Shimano and other 24mm diameter thru-axle cranks, as well as improve the system, select this bottom bracket. The package comes with two cups and CeramicSpeed Bearings installed. Coated Bearings feature super smooth CeramicSpeed Balls, hardened-steel races, and a 3-micron thick metallic layer over the races. This addition makes the races smoother and harder, lowering drag and increasing life.