This instrument is designed to be extremely accurate, fast and simple to use in commercial and residential pool applications. Advanced features include automatic temperature compensation; highly stable microprocessor-based circuitry; user-intuitive design; titanium electrode, and waterproof housing. A true one-handed instrument, the PT3 is easy to calibrate and easy to use. To take a measurement, you simply push a button then dip the pen in solution. Results display in seconds.