The chrome vanadium steel electrophoresis process is precision forged, with strong toughness, durability, high strength, and high torque. The two-way conversion design, the entire head adopts the two-way conversion design and only rotates 5 degrees, the maintenance space is narrow and convenient, and the actual operation is more convenient and efficient. Made of high-quality chrome vanadium steel, the overall heat treatment has high hardness and large torque. The head is quenched to high hardness to ensure safe torsion. 16-18 mm / 18-21 mm / 17-19 mm / 19-22 mm / 19-21 mm / 19-24 mm / 21-22 mm.