21 INCH. Center cap. mestral sparkle. A single Wheel Cover for a vehicle, which provides protection and style to a Wheel that utilizes a Wheel Cover. Part is a kit that contains 4 center Caps. Part is a set of 4 center Caps. Part is a set of 4. Wheel center Caps which Cover the center opening of a Wheel, which gives access to the Wheel hub.. CENTER. Hub.