The weather protection grid, System 772.5XL, from MLL Hamburg, is a ventilation grid made of aluminium with a free ventilation cross section of 59%. The System 772.5XL is equipped with a Z-slat of the heavy series of type 070XL, which in turn is installed in enclosed frame 702.5 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.