The MR15307 - ABEC 5 by Enduro Bearings is a high-quality radial bearing designed specifically for bicycles. Made with 52100 High-Carbon Chromium alloy races and grade 5 balls with 90% fill, this bearing is built to last. It is also coated with high-pressure, water-proof grease to ensure optimal performance even in wet conditions.The LLU/LLB seal combination on these bearings is specially designed to provide maximum protection against contamination from water or dirt. The outward-facing LLU seal keeps the elements out, while the inward-facing LLB seal reduces seal-drag and keeps the grease in place.Enduro Bearings offers a wide range of options to choose from, including bearings made from High-Carbon Chromium Steel, 440C Stainless Steel, Ceramic-Hybrid, and XD-15 with Ceramic or Stainless Balls. All of their bearings feature deep groove races to accommodate the largest balls possible.The MR 15307 bearing has dimensions of 15mm x 30mm x 7mm and is classified as ABEC 5 with a grade 5 rating. It is suitable for use in hubs and bottom brackets.Choose Enduro Bearings for superior quality and performance.