This unit offers ease and simplicity to testing equipment that relies on a variable signal. It can provide a variable signal and show the actual value of the equipment being tested. It also has the capability to reverse the polarity of the signal. This particular unit compares a proportional hydraulic valve 0 – 10 VDC input signal with the valves corresponding LVDT and can be used to provide calibration or determine functionality. It utilizes standard hydraulic connection cable (on back) and uses a regular 120 volt AC outlet.