■ Material : Aluminum ■ size （Φ）：Φ150，Φ200，Φ250,Φ300，Φ350，Φ375 ■ Accessories : C1 Radial Opposed Blade Damper, C2 Round Guide Vane, C3 Deflector Guide Vane , C4 Round Connection duct ■ Feature: Each layer of diffuser cone is uniform mould pressed. ■ The inner and outer frames are not only removable , but also have two glasses in different height , which is able to adjust the blowing angles of the two different air volume.