Master Flow 4 in. Fresh Air Vent

Master Flow Fresh Air Vents come with a built-in screen to prevent bird entry. They can be used to vent a combustion system or anywhere fresh air intake is needed. Constructed of galvanized steel.|Built-in bird screen|Sturdy galvanized steel construction|Always seal seams with building code approved sealant or duct tape|Install with sheet metal screws|Built-in screen to prevent bird entry|Maximum temperature rating of 390 degree F, minimum temperature rating of-100 degree F