The Extech 445715 Big Digit Hygro-Thermometer with Remote Probe, 14 to 140°F measures humidity from 10% to 99% RH and temperature from 14 to 140°F (-10 to 60°C). It has an accuracy of ±4%RH and ±1°C/1.8°F. This meter also includes maximum, minimum and rest functions and has a rear calibration adjustment post with optional RH calibration bottles.