Deflecto DEFUBGWL Universal, Fits 3" to 4" Vents, White (UBGWL) Bird Guard, 1-Pack Easily installs over any 3" or 4" clothes dryer or bathroom exhaust vent Helps prevent birds form nesting in vents and rodents from entering through vents Strong plastic construction for durability that provides maximum exhaust flow Check periodically and remove lint or other debris, if present Mounting hardware not included