Denso Spark Plug, 4503 PK16TT, Platinum Titanium, Pre Gapped, Twin Tipped, OEM. Twin-tip technology with 11 mm platinum center electrode and 11 mm titanium enhanced ground electrode Improve fuel economy, better acceleration and faster starts than all other single platinum plugs. Purified alumina powder insulator provides exceptional dielectric strength and thermal conductivity, allowing the material to stand up to extreme stress. Purified alumina powder insulator provides exceptional dielectric strength and thermal conductivity, allowing the material to stand up to extreme stress. Twin-Tip design enables faster flame propagation for more complete combustion. DENSO pioneered the use of platinum in spark plug manufacturing. To maximize the longevity and enhance the durability of the spark plug, DENSO applied platinum to both the center and ground electrodes. Platinum offers superior resistance to erosion and corrosion enabling DENSO to create a spark plug capable of consistent performance.