Linear slot diffusers Tangra LD are frame of extruded aluminum profiles with grille of galvanized metal sheet with plastic blades installed on it.  Plastic blades allow manual air flow direction control, depending on the specifics of the room. They give an opportunity for air flow direction control. Joined to the air duct system with a plenum box and flexible ducts. The air flow rate of a one ventilation grille can be from 100m3/h up to over 1000m3/h (27l/s – above 278l/s).