This vent can be used as a dryer or fan vent. It can be exterior wall or roof mounted. This model is far superior to a standard louvered vent in several ways. First, the unique closure system prevents drafts from entering and keeps out leaves and outside debris, which can clog louvered vents. Additionally, the thermal plastic closure doesn’t conduct heat as metal does, and it reflects moisture to retard frost formation. These vents are available with a spring-loaded shuttle for use with low-pressure fans.