Rebar couplers are a new type of internal threaded fasteners, which are suitable for threaded connections. They are screwed into and fastened in the threaded hole of one of the connected parts to form a standard internal thread, and bolts (or screws) are then screwed into it. It is a spring-like internal and external thread concentric body precisely processed with high-strength, high-precision, and smooth-surfaced cold-rolled diamond-shaped stainless steel wire. It is mainly used to enhance and protect the internal thread of low-strength materials. The principle is to form an elastic connection between the screw and the thread in the base, eliminate thread manufacturing errors, and improve the connection strength. The wire thread inserts are embedded in the threaded holes of low-strength engineering materials such as aluminum, magnesium alloy, cast iron, glass steel, plastics, etc., and can form high-precision internal threads that meet international standards. They have high connection strength, earthquake resistance, impact resistance and wear resistance. Function, and can disperse stress to protect the thread of the base body, greatly extend the service life of the base body, and is widely used in electronic applications.