Extra long life iridium plug. Dual needle design. 12 millimeter thread size, 26.5 millimeter (1.04 inch) reach, 5/8 inch (16 millimeter) Hex size, gasket seat, Resistor, 0.5 millimeter fine wire iridium center electrode, 0.7 millimeter platinum needle tipped ground electrode, solid terminal nut, .043 inch (1.1 millimeter) gap, heat range: 24.