Brass Spinner custom gas cap is a direct replacement for your stock Harley gas cap. Of course this custom gas cap can fit bobbers and most custom motorcycles using the same type of fuel tanks. Custom gas tanks with single filler bung will need our right side motorcycle gas cap. Fuel tanks with dual filler bung will obviously need a left and a right side custom gas cap. Stock gas tanks with fuel gauge unit will need our adapter and two right side gas caps (one for the right side and one to go inside our adapter to replace the OEM fuel gauge unit). This chopper custom gas cap is made out of billet brass and mirror polished. Looks great alone or combined with our Brass Motorcycle Oil Plug, Brass Retro Cable Motorcycle Hand Controls, Universal Brass Motorcycle Kickstand, Vintage Custom Forward Controls with Round Holes and Wheel Spinner with Brass Studs.