Bosch 9621 Double Iridium Spark Plug, Up to 4X Longer Life (Pack of 1) Double Iridium firing pin and ground electrode inlay provide 4X longer service life compared to standard copper plugs 0.6mm fine wire firing pin provides superior ignitability and performance 360 continuous laser weld fuses corrosion resistant iridium firing pin to base for increased durability 7 year performance satisfaction guarantee Original equipment, pre-gapped replacement delivering optimum fit, form and function