The Taylor Pocket Sling Psychrometer is compact, accurate and easy to use, perfect for professionals on the go. This compact, portable sling psychrometer measures wet and dry temperatures from the surrounding air and converts them to a relative humidity percentage using the slide rule scale printed on the case. The tough plastic casing is lightweight and durable, and features clear white lettering for easy and convenient measurement. Features a temperature range of 20- to 120-degrees Fahrenheit, and a 10- to 100 percent RH scale. Permacolor display provides quick and easy measurements. Six (6) measuring wicks included.