Also the most important German weather institute, the “Deutscher Wetterdienst” (DWD) uses FISCHER products, as you can see in this movie (at 3:09): Wetterlexikon: Messwiese und Wetterballon
The guy discribes the importance of a real hair hygrometer for the meassurement of the relative air humidity. While explaining different instruments in use at the test field Lindenberg, he shows the FISCHER Hair-Hygrometer 111.01.