The AcuRite Indoor/Outdoor Wireless Thermometer with Remote Sensor displays both indoor and outdoor temperatures in Fahrenheit. It uses a thermometer built into the display to give the indoor temperature and uses its wireless counterpart to read and display the outside temperature . The left side of the display shows the indoor temperature and the right side displays the outdoor temperature. Both pieces of the thermometer run on two AAA batteries (sold separately). The indoor thermometer and the outdoor transmitter can be placed up to 100 ft. away from one another.