DIN 352 · HSS · Three-part set for metric ISO-standard threads according to DIN 13 · Consisting of taper, plug and bottoming · Taper and plug both have undersize · Reinforced shank and four flutes · Taper: marked with one ring, long chamfer · Plug: marked with two rings, medium chamfer · Bottoming: marked without ring, short chamfer · Pitch: 1,25 mm