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