BSA is another way to indicate English threading; it comes from British Standard Cycle. English threading on road bikes indicates a 68mm wide shell, with a 34mm inner diameter and reverse threading on the drive side. It is the most common threaded standard used today. This kit is compatible with 24mm diameter hollow axle cranksets, found on Shimano, FSA, Rotor, among others.Choose between two types of bottom bracket bearings. The Standard Bearings have low resistance thanks to the hardened steel races and our ceramic balls. The Coated Bearings have the same balls mounted on hardened steel races that are coated for increased durability and lower bearing resistance.Included in the package: 2 threaded bottom brackets with bearings 2 dust covers with integrated spacers Spacer tube All Round Grease Decal