The E3.109 is a 14mm, 0.708” reach racing spark 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. Part Number: E3.109; Resistor: Non-Resistor; Hex Size: 5/8"; Thread Reach: 0.708"; Thread Diameter: 14mm; Seat: Taper; Tip/Gap: DiamondFIRE Fixed Gap Cannot Be Adjusted. It crosses with Autolite AR93, AR94; Champion 280, 685, S59YC, S61YC; and NGK 7891, R5724-9. Our unique DiamondFIRE open design forces air gap discharges, creating the preferred edge-to-edge spark path. The design allows replenishment of the spark zone with a fresh fuel/air charge, and exposes the flame front more directly to the piston head than other plug designs. This distinctive spark plug design has proven to simultaneously increase engine power output, reduce gasoline consumption, decrease hydrocarbon and carbon monoxide emissions from the engine, and materially extend the life of the spark plug. Our lawn and garden spark plugs help engines operate more efficiently with a faster and smoother acceleration.