Features:

• The ultimate in the evolution of spark plug technology and performance from the industry leader
• The iridium electrode is 25% smaller than a platinum electrode, and it's just 1/4 the size of a conventional nickel electrode
• Ultra-small diameter center electrode reduces voltage requirement and extends ignition system life
• New metal shell plating has enhanced anti-corrosion qualities

Fits Harley Twin Cams. Spark plug models fit a wide variety of motors.  You're responsible for referencing the exact fitment of NGK plugs for your year, make, and model before purchasing.