straight grooves, progressive tap, HSS-E, TiCN coating, metric ISO-thread, right thread, Tolerance field ISO2 / 6H, forme of taper lead B (3.5-5.5 x P), cylinder shank with square piece, number of teeth 3 Power class N For long-chipping materials with a tensile strength of Rm > 350...1000 N/mm2. Length of taper lead: 4 x P Hole Type: through holes. Designs: M8...M16: N420TC-4, falling through shaft, DIN 376