VDL Diffuser:In terms of cooling or heating, air supply perspective can be achieved by adjusting the blades angle. Because of large scale of wind blowing, it can be suitable for industrial plants or senior activities centers, as well as public places (such as: industrial plants, airports, theaters, bank etc.) Structure: VDL has four different specifications, positive outlets equip with adjustable blades and flow laps. The leaves can be manually adjusted, or by pneumatic device or electrical devi