2PCS Bicycle Bike Ceramic Ball Bearing Rubber Sealed Before Two Bicycles Ceramic Axle Hub BearingsSpecifications:Material: Steel + Nylon + SI3N4 Ceramic + RubberColor: Silver+blackDimension: 42X30X7 mmFeatures:Fit for most Bottom bracket which use BB30\/ 30mm Spindle.Like SRAM\/Rotor\/FSA\/ Cannondale Bikes and so on.Note:For different monitors、 the color may vary slightly. Besides、 please allow some errors of manual measurement、 thank you for your understanding!Package Includes:1 x pair of Bicycle Bearings