This is a fully functional "3-wire" thermostat.  Condition is Used. 

Honeywell TH9421C1004 Vision PRO IAQ Thermostat features 7 day programming and is designed for Up to 3 Heat/2 Cool Conventional Systems and Up to 4 Heat/2 Cool Heat Pumps.

Honeywell Vision PRO IAQ Thermostat provides electronic control of 24 Vac heating and cooling systems in addition to humidification, dehumidification and ventilation all with just 3 wires to the thermostat.. Honeywell TH9421C1004 offers you top-of-the-line features like Touchscreen interaction, a real-time clock, and a large, easy-to-read backlit display.

Features:

• Advanced dual-fuel control
• Three wires to the living space allows for easy equipment upgrade without having to run additional thermostat wire
• Thermostat connects with Equipment Interface Module or EnviraZONE panel to control temperature, humidification, dehumidification and ventilation from a single point in the home
• Automatically raises humidity levels throughout all rooms in the home, moisturizing air to prevent symptoms of dryness and to protect hardwood flooring and woodwork
• Removes air pollutants by exchanging the stale air in a house with fresh, filtered air better than having an open window