The parallel horn has precise dimensions and parallelism and perpendicularity, which can improve the workpiece Provides a practical, reliable and accurate position for operations in drilling, milling, grinding, assembly, etc. Simple, economical and convenient clamping of a group of workpieces. Hardened from high-quality steel to eliminate stress. Powerful and finely ground. Each size is 2 pieces. Each specification is 2 pieces. Working surface accuracy 0.005M.Quenching HRC52-58 degrees.