KKmoon LCD Digital Thermometer Hygrometer Temperature Humidity Meter With Wired External Sensor Indoor / outdoor temperature, indoor humidity display. C / F temperature switch display, comfort display. Memorized MAX/MIN indoor temperature and humidity value automatically. With back stand and magnetic stick at back side, convenient to place. With a wired external sensor that can be strung to the outside of your house to sense external temperature as well as a built-in sensor to simultaneously measure the indoor temperature.