It is a convenient digital tool designed to quickly assess water quality. TDS, or Total Dissolved Solids, refers to the concentration of dissolved salts, metals, and minerals in water. With a simple button press, the meter measures TDS levels and displays results on the screen in ppm (parts per million). Lower TDS values indicate purer water, with pure water registering at 0 ppm. This device is ideal for testing tap water quality and determining when to replace water filters. (Note: The meter does not detect biological contaminants.) The TDS meter is suitable for a variety of applications, including drinking water assessment, water filtration and purification systems, hydroponics (nutrient testing), aquariums, DI systems, swimming pools, spas, and commercial or industrial uses. It is a durable handheld model that comes with a protective carrying case. Designed for reliability, the meter features a built-in digital thermometer and advanced microprocessor technology for accurate and stable readings. It includes an easy-to-read LCD screen and efficient data display for convenient measurement recording. Ideal for use in hydroponics, gardening, aquarium and reef tank maintenance, water ionizers, and various water filter systems. Suitable for testing drinking water, water purifiers, carbon filters, hard water, tap water, refrigerator water filters, reverse osmosis systems, and related filtration applications. Measuring range: 0–9990 ppm, with a resolution of 1 ppm and accuracy of ±2% of reading. Power supply: 2 x 1.5 V (LR44 button battery), not included. Color: Black Material: Plastic Size: 155 mm Package Contents: 1 x TDS Pen Note: The package includes only the items listed above. Other accessories are not included. Note: Lighting and display settings may cause slight variations in the color of the item as shown. Measurement error allowance is ±1–3 cm.