Electric wrench refers to an electric tool used to tighten and loosen bolts and nuts, and is a tool for tightening high-strength bolts. Used for the initial and final tightening of high-strength bolts with large hexagonal heads in the installation of steel structure bridges, factory buildings, chemical and power generation equipment, as well as the initial tightening of high-strength bolts with torsion shear type, and in situations where there are strict requirements for the torque or axial force of bolt fasteners.

A socket impact wrench is a tool consisting of multiple sockets with hexagonal or twelve corner holes and equipped with various accessories such as handles and extension rods. Socket impact wrenches are particularly suitable for tightening bolts or nuts with very narrow or deep indentations. Socket wrenches are mainly used in situations where bolt space is limited, and can only be used with socket wrenches. In addition, when the nut end or bolt end is completely lower than the connected surface, and the diameter of the concave hole cannot be used for open end wrenches, adjustable wrenches, and ring wrenches, a socket wrench is also required.