Honeywell Prestige IAQ Comfort System with RedLINK Technology – YTHX9421R5101WW Kit Includes: (1) THX9421R5021WW Thermostat (white) (1) THM5421R1021 Equipment Interface Module (1) C7089R1013 Wireless Outdoor Sensor (2) 50062329-001 Sensors for discharge and return air The Prestige® IAQ thermostat is a 2 wire high definition color touch screen thermostat, 7 day programmable and selectable for residential or light commercial use. Controls up to 4-stages of heat and 2-stages of cool in a heat pump system and up to 3-stages of heat and 2-stages of cool in a conventional system. Three sets of Universal IAQ contacts to control humidification, dehumidification, and ventilation. Four sensor inputs for wired sensors or dry contact devices. Works with the Equipment Interface Module and RedLINK® accessories including the RedLINK® Internet Gateway, Portable Comfort Control, Wireless Outdoor Sensor and Wireless Indoor Sensor. Now with a 33% smaller footprint, and endless backgr