A flap for a cage for holding electronic devices in a computing system is disclosed. The flap includes a main segment, a first vertical extension, a second vertical extension, a lateral ledge, and a tapered ledge. The first vertical extension and the second vertical extension extend from a first side of the main segment. The lateral ledge extends from a third side of the main segment. The tapered extensions extend from a second side of the main segment and include a flat section and an angled section. The flap has a deployed position and a stored position in the cage. The flap engages with at least two sides of the cage in the deployed or the stored position. The flap may be in the stored position when an electronic component is present. The flap blocks airflow through the cage in the deployed position.