Stainless Steel Cowl Vent with Base - 3" Hose Cowl Vent with Base provides fresh air below decks by trapping air that comes across the top deck and forcing it into your boat&';s cabin or interior. Stamped 304 stainless steel construction with black plastic base. Designed for use with 3" ventilation hose. Installs with four #8 or #10 FH fasteners (not included).WARNING: This product can expose you to chemicals which are known to the State of California to cause cancer, birth defects or other reproductive harm. For more information go to P65Warnings.ca.gov.