Pest barricade completely covers the existing dryer vent cap to help prevent unwanted pests from entering the duct or home and is secured to the exterior wall with screws (not included). Product is on a hinged frame and locks in the open position for easy removal and cleaning of any lint and debris that forms on the cap, pest barricade and duct. Fits over most 3 In. and 4 In. vent caps, including many wide mouth models. Made of durable ABS plastic.