Compact High-quality precision sealed bearings. For use with Mid-size bottom bracket shells. Includes CNC 6061 alloy tube spacer and cones with a selection of spacers to help you dial in your drivetrain. Item Specifications: Bottom Bracket Shell I.D.: Mid, Bearing Type: Sealed Cartridge, Crank Spindle Diameter: 19mm, Interface: 19mm, Bottom Bracket Shell I.D.: 41mm, Defined Color: Silver,