Feature: 1. The 3 in 1 test pen is multifunctional, which can be used to measure PH, TDS, TEMP values. 2. The electrode probe can be replaced and has an automatic temperature compensation function. 3. The operation method is simple, only a mini screwdriver can easily calibrate pH and TDS. 4. Large and clear LCD with backlight ensures that you can read the value easily and it has accurate measurement function. 5. Suitable for water sources, aquarium, hydroponics, hot springs, swimming pools and other water systems. Specification: Item Type: Water Quality Tester Material: Plastic Weight: Approx. 161g / 5.7oz Range: PH Value: 0.00-14.00PH TDS: 0.00-19990ppm Temperature: -50℃ -70℃ (-58℉ -158℉) Resolution: pH value: 0.01PH TDS: 10ppm Temperature: 0.1℃(0.2℉) Accuracy: pH value: ±0.1PH TDS: ±2%FS Temperature: ±1℃ (±2℉) Temperature Compensation: 0°C-50°C (32°F-122°F) Working Temperature: 0°C-50°C (32°F-122°F) Battery: 4 x 1.5V AG-13 Button Battery (Battery Not Included) Applicable Scenarios: suitable for water sources, aquariums, hydroponics, hot springs, swimming pools and other water systems. How to Use: After installing the battery, open the cover and put the measuring head into the liquid to be measured, and the value can be displayed in a moment.. Package List: 1 x Water Quality Tester (Battery Not Included)1 x Manual1 x Screwdriver1 x Protective Shell