7 Day Programmable Or Non-Programmable Thermostat, Unique Program For Every Day Of The Week, User Option 2 Or 4 Periods Per Day, Temporary Override & Manual Hold, Programmable Keyboard Lock, Speed Slide For Easy Programming, Selectable Fahrenheit/Celsius Setting, Adjustable Temperature Swing Differential, Adjustable 2nd Stage Heat Offset, Programmable Air Filter Life Timer Monitor, Easy View Large Back-Lit Display, Energy Use Monitor, Selectable Smart Recovery, Easy To Use, Easy Installation, Dual Powered 2 "AA" Alkaline Batteries Not Included, For Use On Universal Compatibility For Conventional Heat & A/C Up To 2-Stage Heat/2-Stage Cool, For Heat Pumps With Up To 2-Stage Heat/1 Stage Cool, 3-Wire Heat Only Hydronic Systems Hot Water Zone Valves & Gas Millivolt Heaters.