Product Overview The TDS meter is a digital instrument that measures the TDS (Total Dissolved Solids), in the scale of ppm (parts per million) which indicates the amount of solid dissolved in the water. The lower the TDS, the purer the water. EPA suggests that the TDS of drinking water should be below 500 ppm. Besides the purity, water temperature also impacts TDS value. 3-button TDS meter features 2 sensors, 1 for TDS and 1 for temperature. The CPU automatically calibrates the TDS value according to water temperature so the value is always accurate. The Measurement Range is 0 - 9990 ppm at 1 ppm precision, probably the highest in market at this size and cost. It also features a temperature button that turns it into a thermometer with measurement range of 31 - 200F at 1 precision. The compact design and carrying case make TDS a convenient and handy tool for detecting water quality anytime anywhere, either at home, in the restaurant, at work or on the go. Water Quality Testing Must-Have: The TDS meter is a great water quality test tool for drinking water, water filtration and purification systems such as RO systems or DI systems, aquariums, hydroponics (test nutrients), pools and spas, commercial and industrial applications and more Multifunctional and Easy-to-Use: The TDS reading will be displayed on the LED screen in ppm (parts per million); TEMP button- Display temperatures; HOLD button-Lock and record readings; Auto-off Function: Shuts off automatically after a few minutes of inactivity Durable and Convenient: Sturdy plastic housing, light weight(1.76 oz), and included carrying case with belt clip for easy portability to any indoor or outdoor water testing site Accurate and Reliable: Being highly efficient and accurate due to its advanced microprocessor technology, TDS meter is a trustworthy multifunctional TDS pen to know TDS and temperatures of water in any home, workplace, lab, or industrial environment Value Package: TDS meter x 1, Portable Leather Carrying Case with Belt Clip x 1, User Manual with TDS Chart x 1