?The pen ORP meter is professional and ideal tool for testing your water level. Suitable for aquarium pool and environment water. <br> <br> <strong>Features:</strong> <br> Use to measure the amount of Oxidation Reduction Potential (ORP) level. <br> The tendency of the solution to either gain or lose electrons. <br> Clear LCD with backlight. <br> Apply in water sources£¬ aquarium£¬ hydroponics£¬ spas£¬ swimming pools and other water systems. <br> Compact and portable pen-type design. <br> Easy to use and provides instant display of results. <br> <br> <strong>Specifications:</strong> <br> Range: -1999mV ¡« 1999mV <br> Resolution: 1mV <br> Accuracy: ¡À5mV? <br> Operating Temperature: ?0¡æ ¡« 50¡æ (32¡ãF ¡« 122¡ãF) <br> Battery: 4 ¡Á 1.5 V (AG-13) Button Cell Battery (not included) <br> Color: Green <br> Material: ABS <br> Item Size: 15.1 * 3.3 * 2cm / 5.9 * 1.3 * 0.8in <br> Item Weight: 52.4g / 1.8oz <br> Package Size: 17.8 * 7 * 3m / 7 * 2.8 * 1.2in <br> Package Weight: 108g / 3.8oz <br> <br> <strong>Package List:</strong> <br> 1 * ORP Meter (Battery is not included) <br> 1 * User Manual <br> 1 * Mini Screwdriver