2018 New Package &ndash; City Farmer Hydroponic Nutrient TDS Meter, Water Quality Tester for Hydroponic Nutrient Level, Household Drinking Water, Pool, Aquarium Water, one year warranty. Small size, convenient carrying Test liquid TDS/EC value such as hydroponic system nutrient quality, pool, drinking water, pool water or other agriculture purpose. Test liquid temperature such as hydroponic system nutrient quality, pool, drinking water or other agriculture purpose. Hold button to hold the reading for non-sight measuring condition.