Systemair RVK FansSystemair RVK duct fans are high quality intake outlet fans for extracting old, stale air from your grow space or for supplying it with fresh air. The fans are housed in a lightweight yet robust fibreglass and plastic casing with external ports for easy connection to ducting, filters, airsocks or other accessories. The fan can be powered directly from the mains or via a fan speed controller (not included) to regulate the fan speed and air flow.