The water quality monitor can be wired in line between the 120V / 230V electric motor to the supplied power cord on pressure washer units to ensure operators are rinsing with spot-free water. If the water exceeds the spot-free level of quality, a light on the monitor will notify the operator and the machine will power off automatically. Specifically designed for R.O. and deionized treated water; it also serves as an indicator that D.I. tanks are due for a swap. Please specify whether the monitor should be configuered for a 110/120V electric motor or 230V.