When you're passionate about performance, you need a technologically advanced plug. Autolite Iridium XP utilizes an iridium-enhanced 0.6 mm finewire and proprietary platinum sidewire for improved durability and a more focused ignition for better overall ignitability providing optimum performance. Now with a lifetime limited warranty! Thread Size 14mm X 1.25 Reach: 0.708\" Hex Size: 5/8\" (16mm) Seat Type: Tapered Tip Configuration: Long Projection Metal Type: Iridium Terminal Type: Solid