Hexagon nut is used with bolts and screws to connect and tighten the parts.Among them, type I hexagon nut is the most widely used. Class C nut is used for machines, equipment or structures with rough surface and low precision requirements.Class A and class B nuts are used on machines, equipment or structures with relatively smooth surfaces and high precision requirements.The thickness m of type II hexagon nut is thicker, which is mostly used in the occasions when installation and disassembly are often required.Hexagon thin nut thickness m is thin, is used to be connected parts of the surface space is limited occasions