This VentGuard™ roof screen fits over static vents and power ventilators to make sure critters can't get in. Plastic roof vents often have a simple mesh screen or no screen at all, allowing animals to enter your attic and destroy wiring and cause damage. But this roof screen is made of heavy-duty, 18-ga. expanded metal mesh with a black galvanized finish to keep animals out and your house safe. NOTE: Animal control screens should only be installed by qualified roofing or siding contractors.