Square nut is a nut, usually we use in daily life or see most of the six square nut, that is, we commonly known as the snail Bolt. Square nut can be said to be a derivative of hexagonal nut. When the use of hexagonal nut is limited in some occasions or environments, square nut will be used at this time. For example, in some special environments, it is difficult to install hexagonal nuts. The installation tool cannot install hexagonal nuts well, but square nuts are different Some small square nuts can be installed directly by hand, and do not need gaskets, not easy to slip. Square nut also has a characteristic is the manufacture of simple, slightly larger specifications of the square nut process than ordinary six square nut is much simpler. The nuts with small specifications are more simple, and can be directly die-cast. Square nuts are most commonly used in closed environments.