Fischer Instruments 196TH-03F 6" Sauna Thermometer and Hygrometer, USA Version Made from a very light apachi timber wood, the Fischer Instruments 6" Sauna Thermometer and Hygrometer's temperature scale ranges from 90 degF to 250 degF. The Fischer factory for precision instruments was founded in 1945 by aircraft engineer Kurt Fischer, in a small village in the Erzgebirge called Drebach. Still owned and operated by the Fischer family, the experienced engineers and craftsman have designed quality instruments for measuring weather and climate. Precise instruments, well balanced, and well crafted to the finest detail. Distributed exclusively in the USA by Ambient Weather, this piece includes a two year warranty.