Designed to be used with X-Type or EXI cranksets. Manufactured from high strength aluminum & featuring custom retainer bearings. Features - BB Cups are forged & CNC machined from 6066 aluminum. - Tapering wall construction to minimize weight. - Custom 6805 16 ball retainer bearing - Bearings feature our custom triple wiper seal to better retain grease & keep contaminants out. - Bearings are factory filled with Phil Wood waterproof grease -- tested & proven to extend bearing life.