Thermor Bios Indoor Hygrometer with Bios Comfort Scale (White, 4.5-Inch x 7.25-Inch x 1.25-Inch) Indoor hygrometer displays relative humidity and temperature. Measures indoor temp. from -58F to 158F (F/C switchable) F/C switchable BIOS Color Comfort Scale indicates the ideal level of humidity for human health and the health of your home.