The item is a set of 4pcs professional and practical bike headset stem spacer washers in different thickness, which are mainly made of durable full carbon fiber material, and used for oversize forks and stems at 1 1/8" (28.6mm). It is one way to lighten up your bike and get that technical carbon look is to replace your metal spacers with these super light carbon fiber spacers. You will get the 1 1/8" tube size 5, 10, 15, 20mm thicknesses in one package. Features - Color: mainly black. - Material: durable full carbon fiber. - Diameter: about 28.6mm (1 1/8"). - and Full Carbon Fiber Bike Headset Stem Spacer Washers Gaskets. - Use for 28.6mm (1 1/8") Stem. - These are for oversize forks and stems at 1 1/8". With 5mm/10mm/15mm/20mm thickness, they are perfect to get a good fit on your bike. - Four different thickness to meet your different needs. - to use for raising your handle bar. Package list: 1 * 5mm Thick Bike Headset Stem Spacer 1 * 10mm Thick Bike Headset Stem Spacer 1 * 15mm Thick Bike Headset Stem Spacer 1 * 20mm Thick Bike Headset Stem Spacer