A turnbuckle is a three-piece metal connection device designed to gradually increase or decrease tension without twisting the rope or cable it holds. It is composed of a rectangular or rectangular body with screw holes at both ends and two threaded inserts. Threaded inserts usually have a screw hole or hook on the non-threaded end. When the insert is screwed into the valve body and turned in one direction, the screw will be driven out of the valve body, thereby relieving the tension. When the valve body rotates in the opposite direction, the screw is pulled toward the center, increasing the tension. In fact, the name itself describes its function well: a turnbuckle is a belt buckle that can be turned. Turnbuckles are very common in professional wrestling matches-turnbuckles vary in length from 2 inches (5 cm) to 12 inches (30.5 cm). The threaded insert screwed into the valve body is slightly less than half the length of the valve body. Therefore, when the turnbuckle assembly is installed as part of a length of rope or cable, it can almost shorten the length of the turnbuckle body. Turnbuckles are very effective because the process of shortening or extending (directly affects tension) can be completed in very fine increments. Turnbuckles are used for many purposes. For example, in residential construction and decoration, turnbuckles are used to fine-tune the suspension adjustment. Turnbuckles are also widely used on airplanes to adjust the length and tension of rigging, ropes and cables. In all applications, the strength of the turnbuckle should be at least the same as the strength of the fixed cable or rope. The turnbuckle is mainly used to adjust the tension. If used improperly, it may cause injury. Before removing the turnbuckle assembly from the cable or rope, the tension must be completely relaxed and the rope or cable to which it is connected is loosened. Otherwise, the sudden release of tension may cause the rope or the rope to sway. In addition, turnbuckles that are deformed due to the pressure and tension they bear must not be reshaped by heating, because this will reduce the strength of the turnbuckle. One of the most famous uses of the turnbuckle is boxing and professional wrestling.