... Square Air Diffuser: 1.Square shape 2.Made of aluminium 3.Long life time,low cost 4.Easy to install and maintain Air diffuser(round,square ... ,rectangle):1.Diffuser frame is ... air leakage. 7.Standard sizes: 150x150, 225x225, 300x300, 375x375, 450x450mmThe outside view of the air diffusers:Round diffuserSquare diffuserRectangle diffuser Square Air Diffuser ...