Durable premium aluminum alloy construction from Top-Class offers high strength and long lasting durability. The lightweight and robust design features a smooth finish and precise workmanship, enhancing your bike’s appearance. Four spacer sizes are included: 2 mm, 3 mm, 5 mm, and 10 mm for adjustable height to meet your requirements. Specifically designed for 28.6 mm (1-1/8 inch) ahead forks on a variety of bikes, it provides a precise fit and reliable performance. Use scenarios: - Road bikes and commuters can fine tune cockpit height by selecting the appropriate spacers to achieve a more comfortable riding position. - Replacing worn or missing spacers on bikes with ahead headsets to restore proper stack height and steering feel. - Upgrading mountain or endurance bikes with a lower stack height while maintaining compatibility with existing stems and forks for improved control and ergonomics.