Portable handheld design: compact and travelfriendly, so you can test the TDS value of water anytime, anywhere—whether you are traveling, playing, or shopping. Large LCD display with dual readouts: simultaneously shows water quality TDS, conductivity EC, and temperature, with a data retention function for easy comparison over time. Easy to use: turn on, dip the test pen into the water to be tested, and read the results. Lower TDS means fewer total dissolved solids and purer water. Wide compatibility: TDS Meter Digital Water Tester is suitable for checking TDS or EC in any water source, including aquariums, swimming pools, or other environments. Practical use scenarios: Aquarium maintenance: monitor tank water quality to protect fish and plants and guide water changes. Pool care: check TDS and EC to maintain proper sanitizer balance and overall water quality. Onthego testing: verify drinking or emergency water quality while traveling, camping, or away from home.