BB90 is Trek's oversize bottom bracket standard and is found only on Trek road bikes. The shell is 90.5 mm wide and is designed to work with 24 mm spindles and road cranksets and have the bearings inside the shell. The CeramicSpeed bearings are supplied as two bearings, which are then pressed into the frame. These two bearings are comprised of either CeramicSpeed Standard or Coated bearings. Both feature CeramicSpeed super-smooth and super-round balls contained in hardened steel races. The Coated version has a metallic coating applied to the races, making it even smoother and harder, resulting in lower friction and longer life. In the box: 2 BB90 bearings 2 seals 2 dust covers with integrated spacers Universal grease Decal