Fits all Sram GXP road and mountain external bearing cranksets CNC machined alloy cups with ceramic balls and stainless steel races Ceramic bearings offer better corrosion resistance, increased product life and lower friction Ceramic bearings require 78% less energy to move then standard bearings 68/73mm ENG Sram GXP 24/22mm GRY/BLK Alloy/Ceramic 109g