Denso GI3-5 Iridium Saver DDI CoGen Industrial Spark Plug Replaces RB77WPCCDENSO Double Iridium (DDI) Spark Plugs are longer lifespan, hard-wearing spark plugs for gas engines. They are particularly effective when used in bio-gas engines. Denso\'s patented DDI technology extends the spark plugs lifespan and requires significantly less maintenance than competitor plugs.The Iridium alloy pads (developed and patented by DENSO) are located on both the centre electrode and the ground electrode. The two pads dramatically improve wear resistance compared to other Iridium plugs by minimising spark gap expansion. The copper slug inside the ground electrode increases the heat transfer. Increased heat transfer results in lower temperatures and improved plug life. Highly reliable monolithic resistor Powder sealing Hot lock Copper Core Ground Electrode Special Nickel plating with better corrosive resistanceITEM SPECIFICS: Thread: 18 mmHex: 22.2 mmReach: 22 mmGap: 0.3 mmIf you are unsure as to whether this is the correct part for your vehicle, please don\'t hesitate to contact us. Alternatively please use the cross reference table above. Disclaimer: We have taken every care is taken in putting together lists of suitable vehicle compatibilities and component cross references, they are given for general guidance only, and they do not constitute any contractual term, representation or warranty and as such the supplier ( The Green Spark Plug Co LTD ) do not accept any responsibility in respect of any claim whatsoever and howsoever caused arising from the publication of this listing. It remains the responsibility of you (the customer) to check the specification of this item and carefully compare to your original before ordering/installing.