Model: ORP-169A - Color: Blue - ABS plastic material housing - 1.0" LCD display - Measuring range: -1999~1999mV - Accuracy: +/- 5mV - Resolution: +/- 1mV - Waterproof: IP55 - Operating temperature: 0 - 50°C (0 - 122°F) - Powered by 4 x AG13 batteries (included) - Commonly used in measurement of oxidation-reduction potential water disinfection and is correlated with the quality and purity of water - Allows calibration and offers highly reliable measurements and has a wide range of applications in aquarium hydroponics spas swimming pools and other water systems - Comes with a wrench and English user manual