Astra_wheel_nut_cap_v1.stl

I measured the caps on my Astra 18" wheels and they are much longer than other available designs, 320mm long and 17mm wide.

Printing these on the side instead of the more "reasonable" upright will give the part strength for when pulling out of the wheel nut, otherwise it might split unless you print them with nylon or something with great layer adhesion.