Honeywell YTH6320R1001 Wireless Focuspro Thermostat Kit, Programmable Redlink Enabled None Made in USA or Imported 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