straight grooves, progressive tap, intermittent teeth, HSS-E, 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 2-3 Power class N For long-chipping materials with a tensile strength of Rm > 350...1000 N/mm2. Length of taper lead: M2: 2.5 x P M2.5...M16: 4 x P Hole Type: through holes. Designs: M2: N321-3, reinforced shaft, DIN 371, Teeth:2 M2.5...M3: N321-4, reinforced shaft, DIN 371, Teeth:3 M4...M16: N421-4, falling through shaft, DIN 376, Teeth:3