TDS-3 Digital Water Quality Test Pen For Aquarium.

Keep your drinking water quality in check with the TDS-3 Digital Water Tester. It quickly measures Total Dissolved Solids (TDS) in water, helping you check the performance of RO systems, water filters, mineral water, aquariums, hydroponics, and other water sources. Its compact pen-style design, easy one-button operation, and clear LCD display make it perfect for home, office, and professional use.