Systemair Revolution Stratos Silenced AC Fan V2Overview The Systemair Revolution Stratos Silenced AC Fan has set the industry standard for inline fans. It's the go to option for most growers. The unit moves huge volumes of air in silence. The carefully engineered casing and acoustic foam reduce the noise of a standard unit without affecting air flow. The fans are available in 4 versions including 150 mm, 200 mm, 250 mm, and 315 mm. This extractor fan is made to be powerful, sealed, and quiet. The