Mountain MTN9200 Spark Plug Insert Installer Set (Ford) With this item cylinder can be repaired without removing the head - takes a little less than an hour, saving the mechanic about 1 day worth of labor Alloy steel insert is a quality insert that will permanently mount in the spark plug hole and will not deteriorate or fall out Guide insures that tap and reamer are used in a straight line - no installing the spark plug crooked Comes with a DVD that explains job in detail - easy to follow instructions