Specifications: Size: 2mm x1,3mm x1, 5mm x1, 10mm x3 Material: 6061-T6 aluminum alloy Weight: approx. 27 g Suitable for: 28.6mm bicycle front stem fork Inside diameter:28.6mm External diameter:34mm Color:Black Package Listing 1 x 2mm Headset Spacer 1 x 3mm Headset Spacer 1 x 5mm Headset Spacer 3 x 10mm Headset Spacers Note If you go for heavy duty off road ride, you should use aluminum handlebar stem spacers other than carbon spacers. It's stronger than other materials such as Carbon Fiber