By adding a remote temperature probe to your Programmable Heat-Pump LCD Thermostat (sold separately), you'll be able to access remote indoor and outdoor temperature readings. The Remote Temp Interface & Probe is actually two sensors in one. Place the interface base in a remote area to be monitored, such as a basement, attic, or child's room. This indoor sensor will communicate its temperature to your thermostat, but you can also attach the remote probe, which can even be used outside, so you'll always know what it's like out. Mount the interface base up to 500 feet from your thermostat, connecting with 22 AWG wire. The interface sends its temperature reading to your thermostat, which will display the reading in addition to its local reading; the thermostat can then use the average of the readings for temperature control. Connect the indoor/outdoor probe to monitor the temperature in a remote location up to 200 feet from the Remote Temperature Interface.