Leaton Handheld TDS Water Test Meter.Backlight Professional combination TDS EC & Temperature Meter/Pen.3-in-1 Accurate and Reliable Water TDS conductivity tester is a professional water level test instrument, the operation is simple, the appearance of fashion, small size and easy to put in your pocket Measurement Range: Conductivity: 0 -- 9990us/cm;TDS :0 -- 9999ppm ;Degrees Celsius: 0 -- 99.0 ;F: 32 .0 -- 212 .0  F ;Accuracy:  2%F.S Digital aid combo test meter With 3 buttons, shift TDS to EC, with ATC function Hold function, easy to read or record, press "ON/OFF/HOLD" button then remove from test solution ,The battery has a lifelong, with 2 particle CR1620 1.5 battery, can be used for more than 3 years, 5 minutes without operation of the automatic shutdown function, save power. Backlight LCD screen, Green backlight means 40ppm below, Red backlight means more than 40ppm