FSA (Full Speed Ahead) MegaExo 19 Bottom Brackets are for use with 19mm diameter spindles. Features: Features steel cups, composite center tube and stainless bearings Due to varying dimensional tolerances between manufacturers, FSA MegaExo bottom brackets are not compatible with any other brand of crankset Compatible with Gamma Drive cranks Different models of MegaExo bottom brackets are designed to be specific to each model of FSA crankset Specifications: Frame Interface: BSA/English Threaded Spindle Interface: FSA MegaExo Gamma (19mm) Bottom Bracket Shell ID: 1.37 Shell Width: 68mm, 73mm Material: Steel (Cups), Composite (Tube), Stainless (Bearings) Color: Black Weight: 130g