Replaces standard BB90/95 press in bearings commonly found on Trek bicycles with a solid unified thread-together bottom bracket interface. Thread-together bottom brackets provide a secure and stable shell interface for smoother operation and extended bearing life. OS versions are designed for use in frames with worn-out oversized bottom bracket shells. Low-friction dual seals protect the bearings from harmful contaminants. Sealed premium bearings are serviceable. Models available for both Shimano HTII 24mm and SRAM GXP 22/24mm spindles. Requires a special tool for installation (J&B# 610756)