- Surface mounted. Attaches to outside of crawl space foundation wall over 8"x16" openings with screws or adhesive (not included).- Solid ABS plastic vent cover. Won''t rust or rot! Does not go into the opening. Mounts over the opening.- Does not open and close. This is a solid piece vent cover for enclosed, encapsulated, or conditioned crawl spaces.- Designed to be mounted over standard 8"x16" crawl space openings. Screwed directly into foundation wall with a 1/4" masonry bit or construction grade adhesive.- May be painted with a plastic adherent paint. Crawl space vent cover can be insulated by gluing insulation inside the cover.Crawl Space Door Systems designed a durable ABS plastic one-piece solid vent cover to seal the crawl space. Covers the standard 8"x16" air vent or any opening in the foundation wall and fits on the outside surface of the foundation wall and attaches with either fasteners or adhesive. Excellent for closed, encapsulated or conditioned crawl space applications. Please measure your vent opening before purchasing this product. It will only mount over standard.