Modern engine design has seen the glow plugs threads becoming more recessed into the cylinder heads making the repairing of damaged threads more difficult. The unique Laser design, utilising fitting tools with reduced dimensions at the working end makes access to recessed plug threads easier. The universal use of small thread sizes like M8, M9 and M10 has led to increased thread damage on glow plug removal. Kit includes large and small taps, reamer, inserts and insert fitting body. 4 bolts,sizes: M8 x 1mm, M9 x 1mm, M10 x 1mm and M10 x 1.25mm. The fitting bolts supplied are specially manufactured from high tensile steel to ensure the tools will last much longer and not stretch in use. EU Registered Design. Made in Sheffield.