Up for auction is a large mm, used, unknown maker spark plug with an unusually large center electrode. The shape of this plug tends to make me believe it is of a VERY EARLY design. PLEASE be advised of cracks in the top and lower part of porcelain.Anyone wanting to learn more about antique spark plugs is invited to join the Spark Plug Collectors Of America through their website Please note if you are a winning bidder from other than USA , I will forward you an invoice for shipping charges after getting your mailing info. Also be advised of import duties, taxes and charges (typically collected upon delivery or pickup) are the buyer’s responsibility and are NOT included in the item price or shipping charges. Please check with your country’s customs office prior to bidding/buying to determine what these additional costs will be. I always mail out items to USA with USPS delivery confirmation number and email the winner with info.