Feature: 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 °F 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 Pen1 x Instruction Manual1 x Storage Box Note: 1. The instrument is replaceable electrode structure, so in normal use, please do not unscrew the electrode fixing ring, so as not to enter the water caused by instrument failure;2. The life span of the electrode sensor will vary according to the frequency of use, so the electrode should be replaced when the test is not allowed;3. This instrument is used to determine the size of hydrogen content dissolved in water generated by hydrogen rich water generator, do not use it on acidic and alkaline ionized water, iced water above 50℃, below 0℃, fruit juice, tea, coffee and other liquids.4. All data are measured manually, and there are certain errors in the measurement results.5. Do not mix old and new batteries.