Frame and deflection blades are of high quality extruded aluminum profiled construction with the advantages of corrosion resistance and rigidity. Air distribution can be changed vertically or horizontally by means of deflection blades without changing the air flow rate. These blades can be fully adjusted from face opening. Air flow rate can be adjusted by fixing hit and miss damper at the rear side of the diffuser. Damper blades are adjusted from the face opening. Dampers are designed in a unique way that it can be used as an equalizing grid.