Ambient Weather Fischer 125-01 Instruments Laboratory Grade Indoor/Outdoor Thermometer with Synthetic Hair Hygrometer The 125-01 is a laboratory grade thermo-hygrometer for accurately measuring indoor and outdoor conditions The stainless steel housing is vented for fast and accurate readings when mounted inside our outside in a shaded, protected area The hygrometer includes a set screw for calibrating the humidity A spirit thermometer is included for accurately measuring the temperature Includes mounting hook for easy mounting