Enhance your bike's performance with the ACB4051K Bicycle Headset Bearing, a premium component designed for precision, durability, and smooth operation. Featuring exact dimensions of 40x51x6.5mm with 36°x36° chamfer angles, this bearing ensures a perfect fit and precise alignment in a variety of bicycle headsets. Made from high-grade steel and sealed for added protection, the ACB4051K bearing offers outstanding resistance to rust, corrosion, and debris, making it ideal for all-weather cycling. Its smooth operation reduces friction, providing a quieter, more efficient ride while prolonging the life of your bike's components. The ACB4051K is compatible with several part codes, including ACB6808, ACB3636-150, MR006, and ACB51H6.5, making it an ideal replacement or upgrade for your bike's headset. Installation is straightforward, allowing for quick and easy upgrades without the need for specialized tools or professional assistance. Specifications: Dimensions: 40x51x6.5mm for accurate fitting Chamfer Angles: 36° inner chamfer and 36° outer chamfer for precise alignment Compatibility: Compatible with ACB6808, ACB3636-150, MR006, W540243 and ACB51H6.5 part codes