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 Shimano HTII 24mm or SRAM GXP 22/24mm spindle cranks into PF30 frames without the need for adapters. Origin8 Nylon composite BB tools are recommended to avoid the possibility of damaging the cups