It can be used as digital frequency counter in less than 300 Tons Punches, Bending machinery and Shearing machinery; it can also be used as a digital frequency counter in Adjustable Sliders, Machinerys travel, and numerical closed heights. The bi-directional control scale is 0-999mm. The instruments alarm will go off when the load exceeds the allowable minimum and maximum limits, which are accurate, timely and reliable. The numeral will increase or decrease by 0.1mm when the shaft completes one cycle, the rotating speed is 800 turns/min.