A. This aluminum spacer for bicycles is designed for various types of bikes, including mountain bikes, road bikes, and fixed-gear bikes. Made of aluminum alloy, it is sturdy and durable, effectively resisting wear and collisions during daily rides and providing reliable support for the bicycle. B. There are six pieces in a set, with one each of 2mm, 3mm, 5mm, 10mm, 15mm, and 20mm. The multiple thickness options can meet different height adjustment needs. Whether you need to make fine adjustments or significant changes to the fork height, it can handle it easily. C. As a fork head tube spacer, it is compatible with various bicycles and can achieve an accurate match. The installation process is simple and convenient. D. During the ride, you can flexibly adjust the state of the bicycle according to your own riding habits and needs, and enjoy a more comfortable and personalized riding experience.