Upgrade your bike's performance with the ACB518K Bicycle Headset Bearing, a premium component designed for precision, durability, and smooth operation. Featuring exact dimensions of 40x51.8x8mm with 36°x45° chamfer angles, this bearing ensures a perfect fit and precise alignment in a variety of bicycle headsets. Crafted from high-grade steel and sealed for added protection, the ACB518K bearing offers excellent resistance to rust, corrosion, and debris, making it ideal for all-weather cycling. Its smooth operation reduces friction, providing a quieter and more efficient ride while extending the life of your bike's components. The ACB518K is compatible with part codes TK518B, MR127, 073E, TH-073, MR110, and R438, making it an ideal choice for replacing or upgrading your bike's headset. Installation is straightforward, allowing for quick and easy upgrades without the need for specialized tools or professional assistance. Specifications: Dimensions: 40x51.8x8mm for accurate fitting Chamfer Angles: 36° inner chamfer and 45° outer chamfer for precise alignment Compatibility: Compatible with TK518B, MR127, 073E, TH-073, MR110, R438 part codes