The weather protection grid, System 622eh, from MLL Hamburg, is a ventilation grid made of aluminium with a free ventilation cross section of 50%. You can gain security and still not have to do without fresh air or ventilation in a room or building. Thanks to the reinforced MLL slats, penetration into the inside is made more difficult. The system 622eh is equipped with a sliding-water safe, Z-slat of the medium series of type 020 in enclosed Frame 602.