20mm DC Blower Fan

https://www.cooling-fan.com/products/20mm-dc-blower-fan/

A 20mm blower fan fan is a small, powerful, and efficient device used in industries for cooling, ventilation, and other similar applications. Unlike traditional axial fans, DC blower fans generate a high volume of airflow through a compact and enclosed structure, making them ideal for restricted spaces, such as inside electronic devices or small appliances that require cooling.