Features: Install a wheel with a 21mm bolt or nut. Just press the bolt down to secure it properly. Improve smoothness of the wheel. Protect the bolt head from corrosion. Various colors to choose from to make your car exterior more beautiful. Features : Color: red, blue (optional) Material: ABS plastic Standard: 21mm Packing size: 16 * 15 * 2cm / 6.35.90.8cm Weight: 45g Package List: 20*21mm Nut Caps 1 * Tool deletion