Honeywell's Wireless Indoor Air Sensor. Red link Enabled. Senses Indoor Temperature And Humidity To Be Used For Control With Prestige 2.0 And Prestige Iaq 2.0 Thermostats And Vision Pro 8000 Thermostats. The Wireless Indoor Sensor(S) Is Used To Change The Sensing Location Of The Thermostat. Sense Temperature And Humidity Remotely, Average Temperature, And Humidify And Dehumidify In Separate Locations. Made in United States. Manufactured by Honeywell.