MaterialOur bicycle headset spacers are made of Quality aluminum alloy, which is very strong and not easy to wear and tear, you can use it for a long time.SizeOur bike spacers for road bikes have an inner diameter of 30mm/1.18inches and an outer diameter of about 52mm/2.05inches, fit for 1-1/8 inch forks, suitable for headphones up to 55 mm and 56 mm.Easy to InstalThe bike headset spacer is lightweight and portable, easy to install and quick to remove, and suitable for most bikes.ApplicationOur bicycle handlebar headset spacer is fit for 28.6mm front stem fork of, BMX, mountain bike, road bike, etc.Bike AccessoriesUseful accessory for bike enthusiasts to DIY their bikes. proper fit to the tube of most bikes.Specification:Material: Aluminum AlloySize Chart:5.2cmx5.2cmx5mm/2.05inchx2.05inchx0.20inchPackage Includes:1 Bike Headset Sealing Spacer(2 Pack)