BSA is another way of stating English threading; it comes from British Standard Cycle. English threading on road bikes mean a 68mm wide 34mm inside diameter shell with reverse threading on the drive side. It’s the most common threaded standard employed today. This kit works with 24mm diameter thru-axle cranks found on Shimano FSA Rotor among others. Choose between two bearings for the cups. Standard Bearings have low drag thanks to hardened-steel races and our Ceramic balls. Coated Bearings have those same balls installed on coated hardened-steel races for longer life and less bearing drag. In The Box 2 threaded cups with bearings. 2 dust covers with built-in spacers. Spacer tube. 10mm syringe of All Round Grease. Sticker sheet.