Nest thermostat saves energy by automatically turning itself down when you're away

Nest Learning Thermostats, 2nd Generation, Model T200577, new in a sealed box.

Works with Alexa for voice control (Alexa device sold separately).
2nd generation design - Nest is now 20-percent thinner and works in 95-percent of homes with low Voltage systems.

Features include:
Auto-Away: Nest saves energy by automatically turning itself down when you're away
Auto-schedule: Remembers the temperatures you like and programs itself. Easy install - most homeowners install nest themselves in 30 minutes or less. After that, it's just a matter of changing the temperature
Remote control: Connect Nest to Wi-Fi to control it from your smartphone, laptop or tablet

Works with 95% of 24V heating and cooling systems, including gas, electric, forced air, heat pump, radiant, oil, hot water, solar and geothermal. Heating: 1,2, and 3 stages (W1, W2, W3) Cooling: 1 and 2 stages (Y1, Y2) Heat pump: with auxiliary and emergency heat (O/B, AUX, E) Humidifier or dehumidifier (HUM, DEHUM) Fan (G) Power (C, RH, RC)