Features： 1、DIGITAL DISPLAY: Digital hydrogen meter adopts LED digital screen display with backlight design, which makes reading data more clear and convenient. 2、DATA HOLD FUNCTION: Pen type H2 meter has data hold function, easy to store and use, easy to operate, just press "HOLD" button to lock the data. 3、BATTERY POWERED: Under the low voltage prompt, when the display is dim and the battery symbol appears at the top of the display, indicating the battery voltage is insufficient, please replace the new battery as soon as possible. 4、PORTABLE DESIGN: Water quality tester adopts handheld design, small size and light weight, does not take up space, easy to carry. 5、WIDE APPLICATION: Hydrogen tester is widely used in environmental protection, food, health, geological exploration, metallurgy, surface water, industrial wastewater, drinking water and other testing. Specification： Item Type: Digital Hydrogen Meter Material: ABS Product Size: Approx. 18.8cm/7.4in Gross Weight: 245g/8.6oz Display: H2 and Temperature Dual Display Measuring Range: 0?2400ppb, 0?2.40ppm Resolution: 2ppb, 0.02ppm Automatic Temperature Compensation: 0?50℃ Operating Temperature: 0?50℃（32?122℉) Temperature Display Resolution: 0.1℃ Temperature Accuracy: ±0.2℃ Auto Shutdown: 10 Minutes Low Pressure Display: Yes ℃ and DegreeF Temperature Conversion: Yes Data Retention: Yes Battery: 4 x LR44 1.5V Button Cell (Shipped Without Battery) Product with Backlight Uses: Widely Used in Environmental Protection, Food, Health, Geological Exploration, Metallurgy, Surface Water, Industrial Wastewater, Drinking Water and Other Testing Package List： 1 x Water Quality Testing Pen 1 x Instruction Manual 1 x Storage Box