When you want to install SRAM or Quarq´s 24/22mm diameter thru-axle crank into a bottom bracket shell measuring 68mm wide and 42mm in diameter, you need CeramicSpeed´s BB30 SRAM GXP bottom bracket.The CS bearings are hand-assembled and installed into aluminum cups that thread together for quiet durability without adapters.There are two bearing options.The first choice is our low drag, long life Standard Bearing, with hardened-steel races and our super round CeramicSpeed balls.The second choice is our Coated Bearing, which uses those same balls installed on coated, hardened-steel races for longer life and less bearing drag.