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 +/-1°F 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