It is a convenient digital tool designed to quickly assess water quality. TDS, or Total Dissolved Solids, refers to the combined content of inorganic salts and organic matter present in water. With the press of a button, this meter measures TDS levels, displaying results on an easy-to-read LCD screen in parts per million (ppm). Lower TDS values indicate purer water, with distilled or pure water registering close to 0 ppm. This device is ideal for monitoring tap water quality and determining when to replace water filters. Please note that it does not test for biological contaminants. This TDS meter is suitable for a variety of applications including drinking water assessment, water filtration systems, hydroponics (nutrient testing), aquariums, deionized water (DI), swimming pools, spas, and general industrial uses. It features a durable, handheld design and includes a protective carrying case. The unit is equipped with advanced microprocessor technology and a built-in digital thermometer for accurate and efficient measurement readings. The device features an easy-to-read LCD display and is powered by two 1.5V LR44 button cell batteries (not included). The meter has a measuring range of 0–9990 ppm with a resolution of 1 ppm and an accuracy of ±2% of reading. Color: Black Material: Plastic Size: 155 mm Package Contents: 1 x TDS Pen Protective case with belt clip Note: Lighting conditions and monitor settings may cause slight variations in the color appearance between the product image and the actual item. Measurement errors of ±1–3 cm may occur due to manual measurement.