The pocket-sized OPR tester has a replaceable single-junction sensor which can be easily switched out, allowing you to save money by using the tester body over and over again. A large LCD makes viewing measurements easy and features a three-color backlight indicating operational mode blue for measurement, green for calibration and red for alarm condition. It is ideal for checking dirty water, heavy metals, sulfides, and organic materials.

Additional features include hold function to lock in measurements, self-diagnostic error message, and status icons for measurement stability and low battery voltage. The IP67-rated housing features an easy-to-grip design and floats if accidentally dropped in water when sensor cap is on. Powered by four AAA batteries, the tester can operate up to 400 hours continuously. To conserve power, the unit will auto power-off after 8 minutes of non-use.