Double Deflection Grilles are recommended for application in systems requiring maximum flexibility. The front set of blades has the greatest effect on the air pattern and therefore should be selected based on particular requirements. Vertical front blades will control the spread and throw distance of the air pattern where as horizontal front blades will control the rise and drop of the air pattern, typically directing warm air downwards or cool air upwards along the ceiling. The combination of streamlined ‘teardrop’ shaped blades and 20 mm spacing maintains a high effective free area average capacity of 70%, which minimises outlet velocity, reduces pressure drop and assures quiet operation.