Honeywell RTH2510B 7-Day Programmable Thermostat with Backlight Program each day differently - Up to 4 periods per day, Display Options - C or F temperature - 12 or 24 hour clock Easy to Use - Basic operation keeps programming simple, Works with low volt heating/cooling systems including millivolt & heat pumps with or without auxiliary heat Backlit Display, Precise temperature control of +/-1F to maximize comfort Early Start Function - Adjusts the pre-heating/cooling of your home so you are comfortable at your programmed times Filter Change Reminder - Keep your heating/cooling system operating at peak performance&lt;br&gt;