copper rooftop exhaust vent cap with damper (10 inch) generic this rooftop exhaust vent cap is designed to be used with bathroom and kitchen exhaust venting systems. this is a roof mounted vent cap that comes with a damper to prevent back draft, and also with a screen to keep out insects and birds. this product is made with heavy-duty copper. it also comes in a variety of sizes to fit pipes ranging from 4-inch to 10-inch in diameter.