A CEADNESS GAS CAP FOR YOUR VINTAGE NORTON AMD BSA . THIS GAS CAP FITS ALL COMMANDOS AND OTHER MODELS THIS CAP IS MADE IN ENGLAND. IT IS FOR 2 1/2" FILLER NECKS. WE HAVE ALL THE OTHER PARTS YOU MAY WANT OR NEED WHILE REPLACING YOUR PETCOCKS. PLEASE CHECK OUT OUR EBAY STORE FOR ALL YOUR BRITISH BIKE NEEDS.