ADEMCO R8845U1003/U Switching Relay with Internal Transformer 120 V,

The R8845U Universal Switching Relay with 24 V transformer provides intermediate switching of line-and low-voltage devices from a line-or low-voltage controller and is typically applied in Hydronic heating systems. Senses outdoor temperature and humidity to display on RedLINK™ enabled thermostats and accessories. Powered by RedLINK™ reliability. No interference with other wireless devices in the home. Reliable performance in all climates. Installs in minutes. Up to 5 year battery life. 2 month low battery warning. Battery warning displayed on RedLINK™ enabled thermostats. Includes 2 AA Lithium batteries and mounting hardware.