High quality, high speed steel. Metric coarse series thread. Polypropylene storage case. M3 - M6 sizes are 13/16 in (20mm) diameter. M8 - M12 sizes are 1 5/16 in (33mm) diameter, Rozmiar gwintu = M6, Skok = 1mm, Średnica zewnętrzna = 20.63mm, Grubość = 6.