M6 DIN 986 Hexagon Domed Cap Nut with Nylon Insert - A2 Stainless Steel Works in a similar way to Nyloc nuts. The non-metalic (nylon) insert helps to “lock” the nut in place. Sometimes called a prevailing torque type nut Measurements in mm: Thread Size: m = 4.9 mm h = 12 mm s = 10 mm e = 11.05 mm Thread pitch : 1.0 mm A2 (T304) Grade Stainless Steel