Abstract: A ventilation panel comprising a rectangular grating for electromagnetic shielding which is arranged in a rectangular frame and has a cell structure. The grating is resiliently enclosed in the frame by means of a comb-shaped mounting spring which also holds the complete ventilation panel resiliently clamped between two walls of a box with electrical components. The mounting spring further provides an electromagnetic shielding at the area of the separation between the ventilation panel and wall portions of the box. The ventilation panel is used in racks for data-processing apparatus, such as public telephone exchanges.