Venstar T1700 Residential Programmable Comfort Call Thermostat Kit Heat pump compatible, Backlit, color-coded keys and legends, Large, easy to read backlit display, Configurable programmable or non-programmable, LED indicator glows green or red to indicate cooling or heating, Service filter and UV light indicatorsConfigurable manual or auto changeover Service filter and UV light indicators, Fahrenheit or Celsius display, Non-volatile memory, Keypad lock 1-Day Programmable with up to 4 time periods, Auto changeover 2-stage heat, 1-stage cool for use with gas/electric, heat pump, electric & hydronic heat Comfort Call utilizes voice recognition to change the temperature, Completely wireless communication between thermostat and accessory, compatible with home phone systems and fax machines