The Honeywell Home TH8321WF1001/U VisionPRO 8000 Wi-Fi Programmable Thermostat is a top-of-the-line thermostat that can work standalone or with the THM5421R1021 Equipment Interface Module or with the TrueZONEWireless Adapter. With its Smart Schedule feature, this thermostat programs in seconds for any lifestyle, helping you save time and energy. Its patented interview-based programming and installer setup make it easy to set up and use, while the RedLINK™ wireless communication ensures reliable and secure connections. This thermostat is also programmable for annual energy savings, and is ENERGY STAR Certified, making it an eco-friendly choice for your home. With its advanced technology and energy-saving features, the Honeywell Home TH8321WF1001/U VisionPRO 8000 is a smart choice for your home's heating and cooling needs.