C5TF Turbo Plug manufactured by Novarossi. This turbo designed plug, a Novarossi patent, seals at the bottom of the plug instead of at the gasket. This seal takes the threads out of the combustion chamber volume thereby improving performance. Standard and turbo plugs are not interchangeable. They require a Turbo Head or UnderHead. Novarossi has discontined its C5TC model. The only difference was in the amount of metal in the body of the plug. Both plugs had identical coils so performance was nearly identical.
Sold in cards of 5 plugs.