This used instrument is in good cosmetic condition and comes in the original leather carrying case.
The Haenni psychrometer (aspiration psychrometer according to Assmann) has two thermometers (dry and wet-bulb) and a ventilator with a spring motor.
The reading is taken after moistening the wet-bulb thermometer with distilled water and ventilating for at least 10 minutes.
The instrument is susÂpended approx. 1.5 to 2 m above ground in the shade.