Honeywell Daily Programmable Digital Thermostat For use with central gas, oil, heat pumps with auxiliary heat, electric furnaces and air conditioning. Works with millivolt systems. Does not work with electric baseboard heat or multi-stage heating/cooling systems. Up to 4 periods per day programming. Digital 2Heat/1Cool. Easy to read green backlit display. Precise temperature control of /- 1 F degree fahrenheit . Early start function adjusts the pre-heating/cooling. Basic operation keeps programming simple, and installation requires 15 minutes or less. Includes mounting hardware. Programmable 7-Day Programmable, Color White, Width 4-3/4 , Height 3-3/8 , Depth 1 , Pkg Qty 1, Package Type Clamshell