Senses temperature Communicates temperature to compatible Nest thermostats Up to 2-year battery life, One CR2 3V lithium battery (included) Bluetooth Low Energy Range: Up to 50 feet away from your Nest thermostat Up to 6 Nest Temperature Sensors supported per connected thermostat and up to 18 Nest Temperature Sensors supported per home. Requires an installed Nest Learning Thermostat (3rd generation) or Nest Thermostat E