Portable Comfort Control Works Anywhere In Home For New Level Of Comfort and Convenience. Works In Both Zoned and Non-Zoned Applications. Powered By Redlink Reliability. No Interference with Other Wireless Devices In Home. Works with Compatible Redlink Enabled Thermostats and Accessories. Installs In Minutes. Touchscreen Interface with Backlit Display. Can Display Outdoor Temperature and Humidity. Built-In Pager with Audible Noise Helps Locate Device. Screen-Lock Feature Helps Prevent Accidental Changes. One-Year Battery Life. Two-Month Low Battery Warning In Non-Zoned Applications. Take It Anywhere In Home To Sense and Control Temperature. In Zoned Applications, View and Adjust All Redlink Enabled Thermostats From Single Control. Controls Up To 16 Thermostats. Sensor Element: Thermistor.