TROX swirl diffusers type VD are suitable for deployment in both the industrial and commercial sectors. They are suitable for both large heights (e.g. factory buildings, airports, theatres, banking halls) and lower rooms down to 3.80 m (e.g. assembly halls). The blades are adjustable, enabling a horizontal discharge direction for cooling mode and a vertical discharge direction for heating mode. Continuous adjustment can be provided by means of appropriate variable-speed motors. Motors can be deployed in pneumatic or electric versions. The diffusers are connected to the air duct system via the plenum box, in either vertical or horizontal configuration.