Our best solution for replacing OEM PF30 bottom brackets or for new bike builds. The two machined aluminum cups thread together keeping the bottom bracket stable in the frame, increasing bearing life, and simplifying maintenance. This means no more creaking, smoother operation, longer bearing life, and really quick bearing replacement. Bearings: Enduro ZERØ Ceramic Hybrid Color: Black Bottom Bracket/Frame Interface: PF30, PF30A, BBRight™ Press Fit, Specialized Carbon OSBB* Bottom Bracket Shell Width: 61mm* to 79mm Bottom Bracket Shell I.D.: 46mm Over Bearing Width: 68mm in 68mm wide shell Crank Spindle Diameter: 30mm Weight: 106g Compatible with the following Bottom Bracket Standards (46mm BB shell inner diameter): PF30 Cannondale PF30A BBRight™ Press Fit Specialized Carbon OSBB. May need additional cup spacers if BB shell width is 61mm. Compatible with 30mm spindle diameter cranksets.