The roof air vent, System 515L, from MLL Hamburg, is a ventilation air vent with a roof element, made of aluminium and a free ventilation cross section of 52%. The ventilation hood is equipped with a Z-slat of the light series of type 010L. Roof air vents can be produced with all slats from the MLL range. The supporting pillar 005 serves as a vertical post profile, the supporting pillar 006 as horizontal reinforcement.