1、Display modes: Press shift button: TDS - ppm & °C, EC - μs/cm & °C, TDS - ppm & °F, EC - μs/cm & °F. 2、Auto-off function: 5 minute Auto Shut Off feature, so battery won't run down. 3、Compact and portable pen design,easy to operate and storage. 4、Lock function - makes it easy to read and record, press hold button then remove from test solution. 5、Large and clear LCD with backlight, easy to read and accurately measuring functions. Description: The water quality monitor is the useful tool for testing TDS / EC /TEMP of solution level. It looks like a pen, the portable size is good for carrying. Suitable for water sources, aquarium, hydroponics, laboratory and scientific testing, spas, swimming pools and other water systems. Feature: Display modes: Press shift button: TDS - ppm & °C, EC - μs/cm & °C, TDS - ppm & °F, EC - μs/cm & °F. Auto-off function: 5 minute auto shut off feature, so battery won't run down. Compact and portable pen design,easy to operate and storage. Lock function - makes it easy to read and record, press hold button then remove from test solution. Large and clear LCD with backlight, easy to read and accurately measuring functions. Suitable for water sources, aquariums, hydroponics, spas, swimming pools and other water systems. Speciation: LCD screen: 4 digits Automatic temperature compensation (ATC): 0 ~ 50 ° C (32 ~ 122 ° F) Operating temperature: 0 ~ 50 ° C (32 ~ 122 ° F) Battery: 2 x 3v batteries (Not included the battery) Size: 190 x 37 mm / 7.48 x 1.46 inch (appr.) Screw driver length: 95 mm / 3.74 inch (appr.) Usage: 1) Please unplug the electrode sleeve before use 2) Press the switch, place the electrode in the test solution and shake it gently. 3) After the numerically stable, press the "HOLD" button and take it out of the solution to read. 4)Turn off the meter, wipe the electrode, put it to store in package box. Shift between TDS & Conductivity: The factory default TDS data, if the conductivity data of the solution is needed, please touch the SHIFT button, the instrument automatically shifted. Automatic temperature compensation: The instrument with automatic temperature compensation function under measurement mode. Temperature shift: Continuous touch the SHIFT button twice, degrees Celsius and degrees Fahrenheit conversed, the factory default degrees Celsius Package included: 1 x TDS/ EC / TEMP Meter 1 x Screw Driver 1 x Manual