The Primex Low-Profile Roof Vent (RV20) is built for the through-roof exhaust of dryers, bathroom and kitchen fans, stove vents, and intake for furnaces, fresh air make-up, and attic venting. This patented, durable, watertight roof vent is easily installed and adapted to fit 4, 5 or 6-inch ducting for an aesthetically-pleasing, perfect fit every time. - See more at: http://www.primexfits.com/hvacventing/product-type/low-profile-roof-vents/#sthash.r9c5QTIg.dpuf