E3.109 is a 14mm, 0.708" reach plug with a 5/8" hex and a taper seat. It is built to have a cold heat range, non-resistor, and is used a variety of racing applications. E3.109 is a similar to E3.108, but has its own heat range, and has a projected core nose. E3 racing plugs are fitted with its patented DiamondFIRE ground electrode, which is secured with two legs to the shell. This allows for excellent heat transfer, and provides additional stability to the side wire in these high RPM engines. The unique DiamondFIRE ground electrode is proven to increase power, reduce fuel consumption and improve hydrocarbon emissions in long-term use. The E3 ground electrode and full-size center electrode also provides optimal performance over an extended product life.