Flat billet aluminum timer cover protrudes approximately 1/2 inch from the gasket surface for a truly unique look. This spin-on cover is mounted using a chrome plated steel backing plate with the inlcuded screws and a perimeter mounted O ring that prevents the cover from loosening. Fits Big Twin 1970-1999 (except Twin Cam 88 models) and Sportster 1971-1999.