The Hartland Controls HCT-09E0BB06 Transformer is a Class 2 control transformer that converts 208/240V primary power to a stable 24V secondary output for HVAC control circuits. It supplies low-voltage power to thermostats, relays, and safety controls in furnaces, air handlers, and heat pumps. https://www.partshnc.com/hct-09e0bb06-hartland-controls-208240vpri-24vsec-cl2-transfm