2 x 4 cm (8" x 16") Crawl Space Flood Vent: This flood vent features zinc-coated steel and a treated surface to resist corrosion and impact. Installing flood vents in foundation walls allows for the automatic entry and exit of floodwater, protecting your structure and reducing flood risk. This may lead to significantly lower home insurance premiums. Designed for surface mounting over foundation openings in crawl spaces, garages, and full-height enclosures.