Lock Nut / Round Nut / Slotted Nut DIN 981 / KMSize: 10x0.75mm~200x3mm, KM 0~KM 40Material: Steel C1020, C1045, A3. Stainless Steel 201, 304, 316.Surface Finish: Plain, Black Oxide, Zinc Plating.DIN5406 washers match this nut. Size, thickness, style or other specifications can be designed according to your demand.