Requires the use of a 5/8" spark plug socket, or the female square requires the use of a male 3/8" square drive. Used to clean up dirty or damaged spark plug threads on Twin Cam, V-Rod and some Sportster models. Spark plug thread with a lead in (for proper alignment) and flutes (for dirt and chip relief). Also features a 5/8" hexagon with O-ring and female 3/8" square drive.
