FAST, RELIABLE, AND EASY TO USE - Just dip in the TDS meter, stir, and get your results in seconds. No calibration or setup needed, you can use it straight out of the box UPGRADED ACCURACY THAT LASTS - With the titanium alloy probe and the latest sensors, you can get almost exact readings every time. Whats more, the digital TDS water tester can be easily recalibrated for extended precision whenever needed SUITABLE FOR ANY TYPE OF TDS OR EC TESTING - Check the total dissolved solids or electric conductivity of your aquarium, pool, or any water source. You can determine the effectiveness of your RO, DI, or distillation unit, check the nutrient levels of your hydroponic setup, and more Specification: Product: Water Quality Test Pen Material: ABS plastic Model: TDS-A1 Measurement accuracy: 2% Voltage: 3V Battery: CR3032 (not included) Measuring range: 0-9999ppm&0-9999us/cm TDS range: 1~9990ppm EC range: 1~9990us/cm Resolution: 1ppm&1us/cm Test items: TDS value, EO conductivity, temperature Package included: 1 x Digital Water Tester 1 x Manual