Broan Steel Roof Cap for 3-Inch or 4-Inch Round Duct w/ Damper & Birdscreen, Black

Select the Broan-NuTone® 636 Roof Cap to provide reliable rooftop ventilation. Features a black enamel finish and is designed for use with 3 in. or 4 in. round ducts. Includes a built-in back-draft damper, and protective bird screen to prevent small pests from entering duct.