High quality tool material for professional use. Can be used in the narrowest engine compartment if the glow plugs are difficult to access. Allows removal without any damage to stuck and broken glow plugs from the cylinder head. Two special centered 2-step milling inserts with a holder. Thread cutter M6x1, M8x1, M10x1, M10x1, 23 with hex drive, is self-centering and can be used with any standard screwdriver (ratchet / ratchet). The special design of the electrode withdrawal sleeve for pulling out the glow plug.