The weather protection grid, System 752,5Hei, from MLL Hamburg, is a ventilation grid made of aluminium with a free ventilation cross section of 69%. This ventilation grid guarantees efficient air exchange at very low outside temperatures. The slats are equipped with self-regulating heating elements and warm up depending upon the outside temperature. This prevents the slat surface from freezing over or being covered up with snow. The system 752.5Hei is equipped with a heatable Z-slat of the heavy series of type 050Hei in enclosed Frame 702.5. The ventilation grid is used where it is necessary to guarantee free air circulation in order to safeguard the weather protection system reliably from icing and icicle build-up, even in case of outside temperatures below 0° Celsius.