Slotted nut is a hexagon nut with radial slots on the top. It is used together with a cotter pin. After tightening, insert the cotter pin through nut slots and the hole of bolt shank to lock the nut and prevent rotation loosening under severe vibration. Material: carbon steel, stainless steel; finishes: zinc plated, black oxide. Widely used in vehicle axle, heavy machinery and vibration-prone assemblies.