The working principle of the electric wrench of the torsion shear type is mainly used for the final tightening of the high-strength bolt of the torsion shear type. The purpose of the wrench is to break the plum head of the high-strength bolt. When working, the wrench head should be aligned with the bolt head, and the switch can be pulled to start the work. After a few seconds, the bolt plum head will be broken, and then pull out the wrench to pull the trigger to pop out the plum head, which is the end of the work.