Kit Content:12 x NGK Racing Spark PlugsItem Description:Center Electrode Core Material: Copper CoreCenter Electrode Tip Material: Nickel w/ V-grooveGround Configuration: StandardGround Electrode Core Material: Nickel CoreGround Electrode Quantity: 1Ground Electrode Tip Design: Standard OhmsHex Size: 5/8"Insulator Height: 50.5 mmManufacturer Heat Range: 9Pre-Gap Size: 0.032 inReach: 0.75 inResistance: 1 OhmsSeat Type: GasketThread Diameter: 0.551 in