M5 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 = 4.4 mm h = 10.5 mm s = 8 mm e = 8.79 mm Thread pitch : 0.8 mm A2 (T304) Grade Stainless Steel