3 in 1 Digital Water Quality Tester -TDS EC Purity Meter TEMP Test Filter Pen Feature: For checking -TDS/salt (NaCl) levels freshwater aquariums, -ponds and water purification systems. 3-in-1 smart pen combines -TDS, EC, and a temperature meter for improved accuracy. With an Automatic Temperature Compensation and the measuring range of 0-9999 ppm +/- 2%. Lock function, easy to read and record, press HOLD button then remove from test solution. A lot of water in life will be a lot of unclean, but our glasses can't see it, we can detect it by the water quality tester, very practical Measurement Range: Conductivity: 0 - 9999µs/cm; -TDS: 0 - 9999ppm; Degrees Celsius: 0.1 - 80.0°C, Fahrenheit: 32.0 - 176.0°F Resolution: -TDS: 1ppm; EC: 1µs/cm Battery: 1X3.0V (CR2032) (built-in) Accuracy: ± 2% Size: 6 x 1.2 x 0.6 inches (155 x 30 x 15 mm) Package Includes: 1 x Water Quality Tester 1 x Carrying bag 1 x User's manual