Cleveland Controls DDP-106-299X Air Flow Switch is a safety monitoring component designed to detect airflow in compatible HVAC equipment. It works by sensing changes in air pressure caused by blower operation and activating or deactivating an electrical circuit when the required airflow condition is met. Designed for use with compatible furnaces, air handlers, rooftop units, and venti... https://www.partshnc.com/ddp-106-299x-cleveland-controls-air-flow-switch