... diffuser 1. extruded aluminum construction 2. used in return air and exhaust application 3. good quality Detailed ... aluminium diffuser, air diffuser, aluminum diffuser, air grille,ventilation, HVAC 1.Mannual closing. 2.Material Extrude ... square aluminium diffuser, air diffuser, aluminum diffuser, air grille,ventilation, HVACMaterial: AluminumCorlor:white powder coatedSize:Different sizes ...