FEMA Compliant Engineered Crawl Space Flood Vent - Wall Mounted (Black) (8"x16") FEMA Compliant. Engineer Certified. Durable ABS/UV treat plastic. No rust or rot! Surface mounted over the foundation opening. Total Dimensions = 11"x19". Opening within the frame is 8"x16". Flood Vent is a fixed-louvered vent (remains open) with vermin screen. Protects your foundation from rising floodwaters: 205 square feet of coverage per vent. At least two vents required to be FEMA compliant. Engineered Certificates included in the box for the following states: AL, CA, CO, CT, DE, FL, GA, LA, ME, MD, MA, MS, NC, NJ, PA, RI, SC, TN, TX, VA. Flood Vents may help lower your flood insurance premiums! Also works great on garages, sheds, etc.