The bolt is made of alloy steel 42CrMo by precision forging, and the tensile strength ob is 1080MPa. High temperature resistance, high wear resistance and high mechanical properties. The built-in ball bearing rotates 360° without vibration, uniform force and no torque. Smooth rotation, strong and durable. Scope of use: Widely used in industry, logistics, construction, ports, bridges, machinery, coal mines, petroleum, stadiums and other industries. Safety guarantee, high bearing capacity, large bearing capacity, good toughness, fatigue resistance, high efficiency. 100% of each piece is verified by 2.5 times the working force, and 20,000 fatigue tests are sampled.