Circular diffusers with fixed cones DR 160 circular diffusers with fixed cones are suitable for either ceiling and exposed ductwork installation, providing a horizontal air distribution, perfectly suitable for conditioning and ventilation systems, but they can also be used for exhaust systems. The DR 170 model is also available. It is installed with a central screw from the bottom through a mounting bar in the duct. The available accessories include the butterfly damper (only for DR 160) and the distribution plenum with circular side connection for models both with or without insulation. Quick selection The air flow rates and the pressure drop rates are certified according to the UNI 8728 and prEN 12238 standards, by an independent and certified body, in compliance with the legislation in force on energy saving standards Pressure drop Pa 10 < 30 Technical draft DPS plenum Galvanized steel distribution plenum with circular side connection. Without damper. DPS-I plenum Galvanized steel distribution plenum with Class 1 internal polyethylene insulation (6 mm thick). Without damper.