WIRELESS FOCUSPRO? THERMOSTAT: Same great features of the FocusPRO? thermostat - now wireless. Installs in minutes. Displays outdoor temperature and humidity. 1 year battery life. 2 month low battery warning. Dual Fuel enabled. * EQUIPMENT INTERFACE MODULE (EIM): All HVAC equipment is wired to the module. Module receives communication from the wireless devices. * RETURN AIR SENSOR: Works with the Equipment Interface Module to maintain safe indoor temperatures if power is lost at the wireless thermostat. Maintains 62 F for heating and 82 F for cooling. * REDLINK? WIRELESS TECHNOLOGY: Powered by RedLINK? reliability. No interference with other wireless devices in the home.