Wi-Fi enabled thermostat allows for remote access via Smartphone or computer. 7 day programming with 4 program periods per day. Free app Smart Response Technology gives control of thermostat settings. View local weather from app. High/low temperature alerts via email, phone, or web. Precise temperature accuracy +/- 1 F (degree Fahrenheit). Pre-programmed with energy savings schedule. Vacation hold adjusts programming and automatically resumes normal settings. Filter change reminder based on actual run time. Universal compatibility - works with virtually any system type (24V common wire required). Works with 2 Stage or multi-stage heat or cool. 24V. 3.75" H x 5.75" W x 1.25" D.