... with reinforced mitered and welded corners.Spring loaded core,removable without the use of tools.Optional opposed blade damper. ... . Basic InformationBusiness Type:Manufacturer Product/Service (We Sell):Air grille,air diffuser,egg crate grille,air damper,return air grille, ... air vent,ceiling diffuser,air inlet,air outlet,aluminum grille,aluminum diffuser Number of Employees:51 - 100 ...