This rear shock absorber bushing is made of 7075 aluminum alloy and Teflon, with an inner diameter of 12.7mm and outer diameter of 15mm. It is designed for use with mountain bikes and is suitable for shock absorber widths of 12.7mm. The product comes with a DU bushing and is available in various lengths, including 22mm, 24mm, 32mm, 44mm, 50mm, 52mm, 54mm, and 68mm.