The CLOUDLINE PRO S4 is an extremely quiet inline duct fan system that quietly ventilates air in even the harshest environments. With a 10-speed fan controller, it’s easy to optimize the airflow in the grow tents without impacting the performance or efficiency. The ventilation system with a PWM-controlled EC motor has minimal heating and reduced noise levels no matter the speed. The speed controller is compatible with all UIS controllers, permitting high levels of optimization and allows much more freedom for the growers. The exterior is IP44-approved, making it highly resistant to external factors. The CLOUDLINE PRO S4 can be mounted in any direction thanks to the dual ball bearings. Also, the backup memory is extremely useful in situations where the power is cut off unexpectedly. The Cloudline Pro S4 inline fan is suited for up to 100x100x200cm (3.3x3.3x6.5 ft.) areas. Need more power? Consider the Cloudline Pro S6, which suits up to 150x150x200cm (5x5x6.5 ft.) areas. Need even more power? Consider the Cloudline Pro T8, ideal for 150x300x200cm (5x10x6.5 ft.) areas.