The Lambro 6-In. Galvanized Steel Exhaust Hood Vent with 11-In. pipe is ideal for venting through the wall. It features a spring-controlled opening and closing damper that prevents outside elements and air from entering the vent. The damper seals the vent opening when the bath fan, range hood, and microwave are not running. When the appliance operates, the exhaust air pressure pushes the damper open to let the exhaust air escape from the vent. The vent is for new and replacement installations over an existing 6-in. opening. It features an opening containing the wire mesh screen with a net-free area of 18 sq. in., allowing for less back pressure. Removing the screen for an unrestricted opening provides a net-free area of 34 sq. in. The vent's manufacturing material is 26-gauge galvanized steel for durability and longevity. Make sure to check local building codes before installation.