MR 2437 LLB - ABEC-3, Radial Bearing- 24mm x 37mm x 7mm ABEC-3 Radial Bottom Bracket Bearing featuring Black-Oxide treated 52100 High-Carbon Chromium alloy races paired with grade 10 Balls with 90% fill, Mobil XHP 222 high-pressure, water-proof grease., The most common use for this bearing is as a direct replacement bearing for Shimano-type external cup BBs and cranksets with 24mm spindles. The Enduro line of bearings are available in high-carbon chromium steel, 440C stainless steel, ceramic-hybrid and XD15 with ceramic or stainless balls. Our bearings are always engineered with deepest groove races possible to accommodate the largest balls and feature dual-lip seals that ride in a micro-groove creating a full labyrinth to provide superior protection against the elements.