This instrument is designed to be extremely accurate, fast and simple to use in diverse water quality applications. Advanced features include the ability to select from 3 different solution types that model the characteristics of the most commonly encountered types of water; proprietary temperature compensation and TDS conversion algorithms; highly stable microprocessor-based circuitry; user-intuitive design; and waterproof housing. A true, one-handed instrument, the PT1 is easy to calibrate and easy to use. To take a measurement, you simply press a button then dip the pen in solution. Results display in seconds.