It is a cost-effective and convenient digital tool designed to quickly check overall water quality. TDS, or Total Dissolved Solids, refers to any inorganic salts, metals, or minerals present in water. With the press of a button, this TDS meter displays water quality readings on an easy-to-read LCD screen in ppm (parts per million). Lower TDS levels indicate purer water, with pure water measuring 0 ppm. This meter is ideal for testing tap water quality and determining when to replace water filters. Please note that it does not detect biological contaminants.This TDS meter is suitable for a wide range of applications, including drinking water evaluation, water filtration and purification systems, hydroponics (nutrient testing), aquariums, RO/DI systems, swimming pools, spas, and various commercial and industrial uses. It features a rugged, durable design and comes with a protective carrying case. The compact handheld device is widely used across industries and is well-suited for commercial purposes.The included case has a belt clip for convenient storage and portability. Advanced microprocessor technology and a built-in digital thermometer ensure accurate and efficient measurement recording. The clear LCD screen allows for quick and simple reading.Ideal for testing in hydroponic systems, swimming pools, spas, aquariums, reef tanks, water ionizers, and various water filter systems. Also useful for monitoring drinking water, water purifiers, carbon filters, hard water, tap water, refrigerator water filters, hydraulic filters, reverse osmosis systems, and RO filters.Measuring range: 0–9990 ppm Resolution: 1 ppm Accuracy: ±2% of reading Power supply: 2 x 1.5V (LR44 button battery), batteries not included Color: Black Material: Plastic Size: 155 mmPackage Contents: 1 x TDS Pen (Only the above items are included)Note: Lighting and display settings may cause slight color variations between the product image and the actual item. Measurement tolerances allow for ±1–3 cm.