The PermaCoil spark plug series includes a full range of individually packaged kits and inserts. They have application in all types of engines and are available in 10, 12, 14 and 18mm sizes. each kit includes the appropriate reamer/tap and installation tool. For all sizes except 18mm, you choose the reach and quantity of Perma-Coil stainless steel inserts required. Do no use Perma Coil wire spark plug inserts to repair taper seat spark plug ports.