Features 1、Use to measure the amount of Oxidation Reduction Potential (ORP) level. 2、The tendency of the solution to either gain or lose electrons. 3、Clear LCD with backlight. 4、Apply in water sources, aquarium, hydroponics, spas, swimming pools and other water systems. 5、Mini small size, easy to carry with. 6、Compact and portable pen-type design. 7、Easy to use and provides instant display of results. 8、The pen ORP meter is professional and ideal tool for testing your water level. Suitable for aquarium pool and environment water. 9、Clear LCD with backlight.Compact and portable pen-type design. 10、Mini small size, easy to carry with.Easy to use and provides instant display of results. 11、The tendency of the solution to either gain or lose electrons. Clear LCD with backlight. 12、Mini small size, easy to carry with. Compact and portable pen-type design. Specification The pen ORP meter is professional and ideal tool for testing your water level. Suitable for aquarium pool and environment water. Features: Use to measure the amount of Oxidation Reduction Potential (ORP) level. The tendency of the solution to either gain or lose electrons. Clear LCD with backlight. Apply in water sources, aquarium, hydroponics, spas, swimming pools and other water systems. Mini small size, easy to carry with. Compact and portable pen-type design. Easy to use and provides instant display of results. Specifications: Color: Yellow Material: ABS Range: -1999mV ～ 1999mV Resolution: 1mV Accuracy: ±5mV Operating Temperature: 0℃ ～ 50℃ (32°F ～ 122°F) Battery: 2 × 3V（CR1632) Button Cell Battery (not included) Item Size: 14.8 * 2.6 * 1.4cm / 5.8 * 1.0 * 0.6in Item Weight: 37.4g / 1.3oz Package List: 1 * ORP Meter (Battery is not included.) 1 * User Manual 1 * Mini Screwdriver Package List 1 * ORP Meter (Battery is not included.) 1 * User Manual 1 * Mini Screwdriver