This is specially produced for small engines and has a long lead. The 3rd "grounding pin" allows spark to jump the gap in non-battery applications. Black backdrop lens allows for more visibility of spark. Works on most 2 and 4 stroke small engines. Extra-long ground allows for more grounding locations. Hook and loop tape is included for allowing the tool to be strapped facing user. Great for pull start lawn mowers where the user is typically facing the wrong direction of the spark plug.