Nonmercury Sling Psychrometer, 20°-120°F

The wet and dry bulb thermometers are mounted on a bracket that folds down into a handy carrying case which doubles as the sling handle and a psychrometric slide rule. Using the slide rule to calculate relative humidity eliminates the need for any charts. The mercury filled thermometers are graduated in 1° increments with a range of 20° to 120°F.