The chamfered round nut is a component used to tightly connect machinery and equipment, which can be fastened together with nuts and screws of the same specification through the internal threads.

There are many types of trimmed hex nuts, with common ones including GB, BS, ANSI, and JIS nuts. Nuts are categorized by material into carbon steel, high-strength, stainless steel, and plastic steel, among others. They are further divided into standard, non-standard, (old) GB, new GB, American, British, and German standards based on product properties and corresponding national standards. Different sizes and thread pitches result in various specifications. Generally, GB and German standards use M to denote size (e.g., M8, M16), while American and British standards use fractions or # to indicate specifications.