Shape and structure: The main body is a regular hexagon, with flat and symmetrical sides, which can be compatible with various tools such as open-end wrenches, wrenches, and socket wrenches; the interior has standard internal threads, which match bolts of the same specification; depending on the thickness difference, it can be further divided into standard hexagonal nuts (with moderate thickness, suitable for general scenarios), thin hexagonal nuts (with thinner thickness, suitable for compact structures with limited space, such as precision instruments), and thick hexagonal nuts (with larger thickness, stronger resistance to shear and torque, used for heavy-load equipment). Application fields: Cover almost all scenarios requiring fastening, such as mechanical assembly (machinery, motors), construction (steel structure connections), automobiles (chassis components fixation), household appliances (washing machines, air conditioner shells), etc.