NGK Standard Series spark plugs are designed for stock replacement applications. These plugs have a hotter spark, which means better combustion–and that improves performance, while producing less harmful emissions. Specifications: Shorty Spark Plug: No Resistor: No Manufacturer Heat Range: 5 Electrode Tip Material: Nickel alloy Electrode Core Material: Copper Insulator Type: Projected Spark Plug Thread Size: 14mm Spark Plug Reach: 0.750 in. Spark Plug Seat Style: Gasket Wrench Diameter: 13/16 in. Ground Strap Quantity: One Quantity: Set of 4. What's in the box Set Of 4 Spark Plugs