TDS meter for testing of any water quality raw water,pure water,RO purifier water....Digital LCD with cover case....Battery included and can the water tds in ppm unit.....TDS is states for total dissolved solid in the water..The Digital TDS Water Meter is ideal for testing applications such as hydroponics and gardening, pools and spas, aquariums and reef tanks, water ionizers, Water Filter. Drinking water and more. TDS Water Meter is ideal for testing applications ideal drinking water, Water Filter, carbon filters, spring water, hard water, average tap water, Refrigerator Water Filter, Water Filter, brita filter, Reverse osmosis, reverse osmosis filter.