Scope of delivery: This set contains 4 locking caps + 16 regular caps, which normally corresponds exactly to the number of tire nuts on a car. Material: ABS plastic. Useful caps: Cover the heads of screws and nuts on your car, protect them from corrosion, make old nuts or bolts look like new; your car tire looks more beautiful from the outside. Note: Universal caps fit 17 mm hex wheel bolts except Q7. Easy installation: Simply slide over the top of your existing nut or bolt for easy installation.