ABEC-5 Radial Bottom Bracket Bearing featuring 52100 High-Carbon Chromium alloy races paired with grade 5 Balls with 90% fill, high-pressure, water-proof grease. Designed specifically bicycle applications, the LLU/LLB seal combination on these bearings utilizes a more protective full-contact, dual-lip, labyrinth (LLU) seal facing outward, towards the elements, to reduce contamination from water or dirt, while the lighter-contact (less seal-drag) LLB seal face inward to keep the grease where it belongs.The most common use for this bearing is as a replacement bearing for Shimano external-cup, bottom brackets with a 24mm OD spindle cranksets.Bearing Code: MR 2437Dimensions: 24mm x 37mm x 7mmABEC: 5Grade: 5Seals: LLU/LLBGrease: Kyodo Yushi PS-2Application: Hubs, Bottom BracketsWeight: 31.10g