The Enduro MR 2437 LLU/LLB A5 ABEC-5 Radial Bearing is a high-performance 24x37x7mm bottom bracket bearing engineered for bicycle applications, commonly used as a replacement for Shimano external-cup bottom brackets with 24mm OD spindle cranksets. It features durable 52100 High-Carbon Chromium alloy races and grade 5 balls with 90% fill, packed with high-pressure, waterproof grease. The innovative LLU/LLB seal combination provides superior protection: a robust gray LLU seal faces outward to repel water and dirt, while a low-contact black LLB seal faces inward to maintain grease integrity, ensuring smooth and reliable performance.