The Cleveland Controls RFS-4100-078 0.17" Low Air Flow Switch is an air pressure sensing device designed to monitor airflow in HVAC systems. It operates by detecting changes in air pressure through a diaphragm mechanism that activates an electrical switch when airflow falls below the specified set point. This switch helps verify proper blower operation, detect insufficient airflow, an... https://www.partshnc.com/ns2-1015-00-cleveland-controls-30-wc-pressure-switch