Prime Evo Fans offer even greater efficiency than standard Prime fans. Manufactured in Germany, Prime Evo fans are built with powerful motors, strong injection molded housings, and a mixed-flow impeller design. Steplessly controllable, energy saving EC motors produce higher airflow rates while cutting energy costs with reduced power consumption. Six-inch models feature built-in three-speed control that provides the ability to adjust airflow as needed. Choose Ruck Air Movement fans to provide power and efficiency for all of your ventilation needs.