Spark Plug Thread Insert Kit - 14mm 302176For the repair and service of dirty plug holes in aluminium cylinder heads Solid steel inserts replace damaged threads and eliminate the possibility of coil wind out Manufactured from drop forged heat treated steel for maximum service life and durability Installation: Carefully tap out the damaged thread using the tap supplied. The repaired thread will enable the screw insertion of one of the above steel inserts depending on length Note: Tool used by