This SmartRack® exhaust fan is ideal for maintaining a constant flow of air within your small wiring closet. Better airflow keeps your valuable rack components cool, helps boost system performance, and avoids costly equipment failures that lead to downtime, damage and data loss. Two high-performance fans mount on either side of the wall of your wiring closet to either pull warm air from the inside or draw cool air from the outside. The high-speed ball-bearing 120V fans are capable of circulating air at 475 cubic feet per minute (CFM). The unit comes with a replaceable filter for keeping dust away from your electronic equipment. Accepts filters commonly found at home improvement stores (9.75" x 15.75")