This is a new style of supply air grille with adjustable blades.Based on the general supply ari grille,it adopts aerodynamic theory and industrial design.This aluminum grille has two models:double--layer and single--layer.Generally,the double--layer products' design is:short blades in the face while long blades in the back;For single--layer products,blades are parallel to the short side of the frame.Aim to reduce the air--flow resistance and noise.The blades are streamlined design.With the removeable core,it is easy to install and clean,suitable for the central air--conditioning system.