The weather protection grid, System 622AG, from MLL Hamburg, is a ventilation grid made of aluminium with a free ventilation cross section of 50%. The system 622AG is equipped with a sliding-water safe, Z-slat of the medium series of type 020, which in turn is installed in the suspendable Frame 602AG 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.