The rebar end coupler is a device that is used instead of the reinforcement end bend in the structure, and in terms of appearance and size, it reduces the ratio of the rebar, especially in the beam-to-column connection area. The end coupler can be used in almost all parts of the building. To use this coupler, the end of the rebar must be threaded, which can be done at Sahand factory or at large projects. The task of this coupler is to reduce the amount of rebar used in the structure in addition to providing the strength of the structure. It is also easy to close. Now, a question may be raised here, what is the reason for the bend at the end of the rebar and what is the need for this. In the following, we will provide explanations about the bending of the end of the rebar.