The easy-to-install Imperial 4-in Premium Roof Vent Cap helps remove humidity from the exhaust area, inhibiting moisture that can cause damage to your home. It features an anti-gust damper system that stops the back-flow of exhaust air, and a plastic screen that helps to prevent pests from entering your attic. The vent cap is tall for superior performance on snow-covered roofs and its distinctive design helps keep rain and snow from entering the attic. It also has an optimum venting angle for minimal pressure drop. Built to last, the heavy-duty roof vent cap is made with a paintable powder-coated steel construction and features a seamless one-piece base. It is ideal for use with bath ventilation fans and can be used in clothes dryer applications only when the plastic screen is removed. This vent cap is intended for shingled roof installation and is designed for 2/12 to 12/12 roof slopes.