Start and remove spark plugs in deeply recessed cylinder spark plug holes. Set includes 3" and 6" plug starters. 6" length is designed for coil-on plug applications and other engines with recessed spark plugs. The shorter version is for other applications where space is limited Can't reach or safely start spark plugs in deep recessed holes? This kit contains the tools to fit most spark plugs especially coil-on-plug. Tools are made of flexible, heat-resistant plastic to reach into recessed areas or over, under and around hot manifolds. Shaft is stepped to grip insulator. Non-slip, black grip surface for sure handling.