The weather protection grid, System 622V, from MLL Hamburg, is a ventilation grid made of aluminium with a free ventilation cross section of 47%. The system 622V is equipped with a penetration safe V-slat of the medium series of type 020V, which in turn is installed in enclosed Frame 602 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.