This quality tool has been designed specifically to help in the removal of 12mmhexagonal diesel glowplugs from the cylinder head.The tool has an 8mm hexagon fitted to one end, which fits the electrical supplyretaining nut found on the end of the glowplug. The 8mm hex has a retaining ringwithin it so that the small nut doesnt fall out once it has come off the glowplug. Thisfeature also makes it much easier when reinstalling the nut.The 12mm end will fit the most common glowplugs, and the handle has been madeextra long to cope with the stresses involved in initial loosening of these extremely tightfittings. The ratchet has a reverse lever so that it can be used for replacing theglowplugs as well.