CeramicSpeed BB30 Bottom Bracket. Features: Save watts and ride faster with guaranteed lowest friction, optimized power transfer, and longest product lifetime BB30 bottom bracket standard, BB30 for 30mm spindle cranks are a pair of CeramicSpeed bearings while BB30 for 24mm and 29mm spindle cranks have machined aluminum cups with CeramicSpeed bearings Coated: metallic layer that covers bearing races making them 75% harder than steel. Even lower friction and highly resistant to corrosion Standard: low drag with hardened steel races and ceramic ball bearings Offered in 24mm for Shimano, FSA, Race Face, etc, 28.99mm for SRAM DUB, and 30mm spindles 24mm and 29mm in the box: 2 cups, 2 dust covers with built-in spacers, 4x1mm spacers, 10mm syringe of All Round Grease, and sticker sheet 30mm in the box: 2 bearings, 2x1mm spacers, 2x0.5mm spacers, o-rings, 10mm syringe of All Round Grease, and sticker sheet Specs: Model:standard Interface:29mm spindle Shell:BB30 Width:68mm Color:black