Equipment Interface Module, Compatible Brand and Series Prestige, RedLINK, VisionPRO, Compatible Manufacturer Model Number THX9421R5021, Function Control 4H/2C stages in a heat pump system or 3H/2C in a conventional system, Includes Duct Sensor, Equipment Interface Module, Key Features Four Sensor Inputs, Overall Depth 1 5/8 in, Overall Height 9 5/16 in, Overall Length 4 13/16 in, Wireless System Compatibility RedLink, Gray, Standards ASHRAE 62.2