Cleveland Controls RSS-495-011 is an SPDT air pressure switch kit with a range of 0.25″–1.0″ WC designed to monitor and control airflow in HVAC systems. It works by sensing differential air pressure and activating or deactivating electrical contacts when set limits are reached, ensuring proper fan, draft inducer, or blower operation. https://www.partshnc.com/rss-495-011-cleveland-controls-2510-wcspdt-airsw-wkit