For use on Ronal rims with a 76.0 mm center bore on cars with a 65.1 mm hub (Volvo). The adapter ring is made of special nylon plastic. Impact, chemical and weather resistant. Before installing the adapter ring, check that the center bore of the rim and the centering collar of the hub are free of rust and dirt. Clean the surfaces if necessary. Before installing the wheel with the adapter ring under the car, make sure that you use the correct size adapter ring and that it fits the rim and the car!