DENSO PLATINUM TT SPARK PLUGS FOR TOYOTA MR2 MK3 ROADSTER ZZW30Denso Platinum TT Spark Plug Set DENSOs revolutionary Twin Tip design is a combination of durable precious metals Platinum and Titanium. The center electrode is created using durable platinum alloy that allows for the reduction of the tip size to 1. 1mm in diameter, while maintaining the life of the plug. The Titanium enhanced alloy on the ground electrode also increases durability, which is critical to minimize tip erosion and achieve the new Twin