This document introduces the features and characteristics of the T3300 series thermostat, including single-stage heat pump compatibility, zone system compatibility as a master thermostat, low battery indicator, Fahrenheit/Celsius display option, adjustable range from 45°F (4°C) to 90°F (32°C), accuracy within ±1 degree, adjustable temperature differential of 0.5-1.5 degrees, low temperature freeze protection, etc.