Three-way airflow amplification system combines helix energy recovery, progressive flow acceleration, and Venturi-effect volume enhancement to create a strong, focused beam of air Perfect in combination with the NV-FM1 multi-purpose pivoting fan mount and NF-A12x25 series fans (e.g. 5V PWM models with USB adaptors for running them off power banks or USB PSUs) Ideal for creating ultra-quiet desk or room fans that provide serious ventilation even at extremely low fan speeds and can therefore run virtually inaudible Excellent for ambient ventilation applications where fans are required to blow air across a room or other bigger spaces at low noise levels Easy installation using the supplied screws