The Greenheck 385806 Plug-In Dial Potentiometer is a precision control component designed to adjust fan speed and airflow in HVAC ventilation systems. It operates by varying electrical resistance, allowing users to fine-tune motor speed for optimal system performance. Commonly used with Greenheck fans, ventilators, and air handling units, this potentiometer provides accurate airflow c... https://www.partshnc.com/385806-greenheck-plug-in-dial-potentiometer