The weather protection grid, System 732, from MLL Hamburg, is a ventilation grid made of aluminium with a free ventilation cross section of 43%. The system 732 is equipped with a Z-slat of the heavy series of type 030, which in turn is installed in enclosed Frame 702 by means of a proven clip technology. The slats fastened with the MLL clip system are also removable afterwards for repair work on on the facade or similar purposes.