Nail-On Vapor Barrier Box - Wall OutletDescription Some items may require minimum order quantities, which can be changed in your shopping cart. Nail On Vapor Barrier Box Wall Outlet Our Nail On Vapor Barrier Box features built in flanges and gaskets that form a protective barrier against air infiltration, enabling installers to meet local codes where required. The vapor barrier's benefit can be noticed in applications where temperate air, such as warm or cool, passes through wall outlet