1.Used for precision measurement and in spection precision grinding, EDM and wire-cutting machine ,etc. 2.Made of high -quality alloy steel. The hardness of working surface reaches HRC55-60. 3.Easy clamping,effivient and labor-saving,can reduce the labor intensity of employees. 4.The high force mechanism can set the clamping force at any timem,andrepeated use many times to maintain a considerable clamping force,and consistent accuracy,and designed to have clamping force overloadprotection device 5.Big opening,it is suitable for large-scale work to do precision machine.