Increasing air to flow from bottom to top is part of airflow management. The Vertiv VR Roof Fan needs to be paired with the Networking Roof Panel for a zero U application. The Vertiv VRA2007 is a 120 VAC Top Fan Kit. Maintaining the efficiency of your network's cooling system not only decreases the wear-and-tear on your IT equipment, it assists with sustainability and helps make less of a carbon footprint.