PRE SHAVING GEAR HOBS ,PRE-GRIND GEAR HOBS ,WORM GEAR HOBS,SEMl-Toppling GEAR HOBS ,inserted BLADE GEAR HOB ,Fine Pltch Gear HOB Detailed Product Description Class AA,A,B. mm Module Pitch Circle Dia, Overall Length Hole Dia. 5 60 105 22 6 66 125 27 7 63 110 22 7 77 130 27 8 64 120 22 8 88 150 27