describe It is an easy to use instrument for testing the quality of drinking water, aquarium, swimming pool, etc. It uses sensitive probe, which can test TDS quickly and accurately. Small size, light weight, easy to carry anywhere. Features: The portable water test pen adopts a sensitive probe, which can test the TDS of water. It is simple, accurate, fast and stable. Remove the protective cover; Open the tester, immerse the electrode in water and stir gently; Wait for the reading to stabilize and save the value; Clean and dry. The digital screen provides clear display, greatly improving the reading experience. Battery operation, low power consumption, long service life. The water quality analyzer can test the TDS of drinking water, tap water, water purifier, aquarium, swimming pool, hydroponics, aquaculture, agriculture, etc., with simple appearance and exquisite technology. Compact and portable. Note: 1 TDS is one of the water quality indicators; You can't just rely on it. Due to manual measurement and different lighting conditions, the size and color may vary slightly. Thanks for your understanding. Measuring range: 0-9990p Resolution: 2% - 3% Resolution: 1PP Built-in battery: TDS-M2: 2 * 1.5V LR44 button battery TDS-M6: 3V CR1225 button battery Item size: 134 * 25 * 14mm/5.28 * 0.98 * 0.55intds Package includes: test pen * 1