(5R6AG)Fits late '78-'84 Shovelhead and '84-'99 Evolution 1340-equipped models or use in place of Nos. 5R6A and 5RL. A special thread and shell coating ensures quick and easy removal from aluminum heads and resists corrosion. A gold palladium insert extends life and improves resistance to corrosion. The tapered tip provides better spark exposure to air/fuel mixture and allows the mixture to flow more easily through gap area for maximum combustibility. Fouling resistance is improved with smaller diameter center electrode wire and insulator tip. Plus, a copper-cored ground electrode runs cooler for extended life.