4" Inline Duct Fan Blower with 120CFM Airflow Rate Brand new Upgraded 4" Inline Duct Fan/Blower with 120CFM Airflow Rate & Aluminum Fan Blade! Brand new Upgraded 4" Inline Duct Fan/Blower with 120CFM Airflow Rate & Aluminum Fan Blade! Exchange stale air with fresh air to keep temperature or humidity under control and cool your reflector with this mini blower. It's also an excellent ventilation for home use; Safe and environmental friendly Perfect for ventilation of Grow Room or air cooling of grow light reflector