BB90 is the Trek oversized bottom bracket standard and is only found on Trek road bikes. The shell is 90.5mm wide and is designed to work with 24mm spindles and road cranks and have the bearings inside the shell. The CeramicSpeed Bearings come as two bearings, which are then pressed into the frame.
Those two bearings consist of either CeramicSpeed Standard or Coated Bearings. Both feature super smooth, super round CeramicSpeed Balls contained in hardened-steel races. The Coated version has a metallic coating laid onto the races, making it even smoother and harder, resulting in lower drag and longer life.