It is a convenient digital tool designed to quickly measure the overall water quality by detecting Total Dissolved Solids (TDS). TDS refers to the combined content of inorganic salts and organic matter present in water, including minerals, metals, and salts. With the push of a button, this meter provides a TDS reading displayed on the screen in parts per million (ppm). Lower TDS levels typically indicate purer water, with pure water registering 0 ppm. This device is ideal for testing tap water quality and determining when to replace water filters. Please note that the meter does not detect biological contaminants. The TDS meter is suitable for a wide range of applications, including drinking water assessment, water filtration and purification systems, hydroponics (nutrient testing), aquariums, RO/DI systems, swimming pools, spas, and various commercial and industrial uses. It features a durable, handheld design and comes with a protective carrying case. Equipped with advanced microprocessor technology and a built-in digital thermometer, it ensures accurate and efficient measurement readings. The clear LCD screen allows for easy viewing and quick data interpretation. Ideal for both home and commercial use, this digital TDS meter is useful for monitoring water in hydroponic gardening, aquariums, reef tanks, water ionizers, and various filtration systems such as reverse osmosis, carbon filters, and refrigerator water purifiers. Measurement range: 0–9990 ppm Resolution: 1 ppm Accuracy: ±2% of reading Power supply: 2 x 1.5V LR44 button batteries (not included) Color: Black Material: Plastic Dimensions: 155mm Package Contents: 1 x TDS Pen Note: Light reflection and display settings may cause slight color variation between the product image and actual item. Measurement error due to manual handling is approximately ±1–3cm.