Night-Vision preserving backlight,Waterproof and floats,Time and date, Sensors exposed for fast and accurate readings, Humidity sensor can be recalibrated in the field with Relative Humidity Calibration Kit, Automatically store measurements even when unit is turned off, Manually stores measurements with the press of a button, Customizable data storage - 40000 data points, Graph and recall trends, Customize screens to display user-selected measurements, Data charting, Data upload (with optional interface),Five languages (English, French, Spanish, German, and Italian),User-replaceable impeller, Flip-top impeller cover allows use of other functions while protecting the impeller, US Patent Nos. 5,783,753 and 5,939,645 and 6,257,074,All instruments and accessories are completely assembled in the USA, 5-year warranty