Honeywell Home RTH221B1039 1-Week Programmable 3.5H x 4.75W x 1D (in.), White Product Details ONE WEEK PROGRAMMING: Set one identical program for the entire week with four program periods per day including wake, leave, arrive and sleep. PRECISE TEMPERATURE CONTROL: Precise temperature control of plus/- 1 degree Fahrenheit DIGITAL DISPLAY: Easy-to-read digital display with an intuitive interface for one-touch access to setpoint temperature EASY INSTALLATION: Easy to install yourself and basic operation keeps programming simple REMINDERS: Built-in battery change reminders (2 AAA batteries are required for operation) SET POINT RETENTION: Set point is retained in memory in the event of a power outage DISPLAY OPTIONS: Fahrenheit or Celsius; 12 or 24 hour clock. Note: This thermostat is not backlit. OVERRIDE OPTIONS: Permanent and temporary override capability COMPATIBLE WITH: Heating, cooling and heat pumps without auxiliary heat options Does NOT work with electric baseboard heat (120-240 V), heat pumps with backup, or multi-stage heating/cooling. For indoor use only. This easy-to-operate 1-Week Programmable Thermostat helps make your home comfortable exactly when you want it. Programmable for one week, it lets you customize your schedule with four options ? ?wake?, ?leave?, ?return?, and ?sleep? ? for precise temperature control and added comfort. Simple step-by-step instructions included with the thermostat make DIY installation easy. Condition: New open box 20% RESTOCKING FEES AND SHIPPING WILL BE CHARGED. IF ITEM IS FUNTIONAL OR INCOMPLETE. Your feedback is extremely important to us! If you are satisfied with our service please take the time to give us positive feedback. We tremendously appreciate it! We strive for your complete satisfaction. Likewise, if you have any issues, please contact us first, and we promise we will do our best to satisfy your needs and solve the problem. If we resolve your problem, we kindly ask you to still leave us positive feedback. Your kindness will be extremely appreciated!