The DuraVent 4PPS-WPT is a wall plate designed to be used to trim wall penetration when using two of your polypropylene vent pipes. It belongs to the PolyPro collection that is safe for the environment and is engineered to be resistant to corrosion. With a black finish, it measures 4 inches in diameter. It also includes a gasket when purchased.In cooperation with PlumbersStock.com, DuraVent is making their highly-innovative products available to each of their customers at affordable prices. Get yours now here at PlumbersStock.com!