Crawl Space Foundation Vent Cover Outward Mounted (White) (10"x18") 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.