Check the listing for details. Digital Hydrogen Meter Backlight LED Display Data AMTAST ENH-100. Condition: Used. Listed at 44.99 USD. Condition is used, good. No additional instructions or accessories. Screen protector plastic is still on the unit. Digital Hydrogen Meter Backlight LED Display Data Hold Function Pen Type H2 Meter Water Quality Tester with ATC DIGITAL DISPLAY: Digital hydrogen meter adopts LED digital screen display with backlight design, which makes reading data more clear and convenient. 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. WIDE APPLICATION: Hydrogen tester is widely used in environmental protection, food, health, geological exploration, metallurgy, surface water, industrial wastewater, drinking water and other testing. 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. PORTABLE DESIGN: Water quality tester adopts handheld design, small size and light weight, does not take up space, easy to carry.