This therma-hygrometer simultaneously displays both humidity and temperature in addition to indicating and recording the maximum and minimum temperature and humidity readings. With a cable and external probe it will measure and read both an internal room and external . It will measure temperature over the range 0 to 49.9 o C and also measures humidity between 20 to 98 %rh. The accuracy for temp. is +/- 1 oC , and Humidity +/- 3% at 25%rh.