Specifications: Size: 2mm, 3mm, 5mm, 10mm x 3, 15mm, 20mm Material: 6061-T6 Aluminum Alloy Spindle Diameter:9/16", Inner Diameter:28.6mm Color: Black Features: Suitable for: 28.6mm bicycle stem fork Made of high quality aluminum alloy, environmentally friendly, sturdy and durable. Perfectly suitable for 28.6mm stem fork of mountain bike, road bike, etc. Lightweight and easy to install. Package includes: 1 x 2mm Headset Spacer, 1 x 3mm Headset Spacer, 1 x 5mm Headset Spacer, 3 x 10mm Headset Spacer, 1 x 15mm Headset Spacer, 1 x 20mm Headset Spacer.