Thread-together bottom brackets provide a secure and stable shell interface for smoother operation and extended bearing life Hybrid AL6061/Nylon fiber cups for a superior fit and noise-free operation Low-friction dual seals protect the bearings from harmful contaminants Sealed premium bearings are both serviceable and replaceable Designed for installing Sram DUB 28.99mm spindle cranks into BB30 frames 68/73mm x 42mm BB30 SRAM DUB 28.99mm AL6061/Nylon Fiber 120g Black