{"product_id":"attwood-66400-3-clamshell-vent-2-3-16-in-corrosion-resistant-plastic-hull-vent-for-intake-or-exhaust","title":"Attwood Clamshell Vent, 2-3\/16 Inch Opening, Large, Part 66400-3","description":"\u003cp\u003eThe attwood 66400-3 is a Large size clamshell vent with a 2-3\/16 inch opening, designed for hull-mounted ventilation on boats. It installs as a complete unit by fastening from either inside or outside the hull, making it flexible for a range of mounting situations. A ventilation hose (sold separately, not included) twists into the bottom of the box, forming a raised water barrier that helps keep moisture out of the ventilated space while still allowing airflow.\u003c\/p\u003e\u003cp\u003eBuilt from corrosion-resistant plastic, this vent will not discolor over time, holding up well in the marine environment. It is designed for either intake or exhaust ventilation and meets ABYC H-2 cross sectional area requirements, so it can be used to help ventilate bilges, engine compartments, or other enclosed spaces that need code-compliant airflow. The clamshell shape sheds water effectively while the box-and-hose design keeps the vent opening clear of debris.\u003c\/p\u003e\u003ch3\u003eSpecifications\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eBrand:\u003c\/strong\u003e attwood\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eManufacturer Part Number:\u003c\/strong\u003e 66400-3\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCategory:\u003c\/strong\u003e Ventilation\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSize:\u003c\/strong\u003e Large\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDimensions:\u003c\/strong\u003e 0.75 inches H x 4 inches W x 5.75 inches L\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWeight:\u003c\/strong\u003e 0.0908 pounds\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMaterial:\u003c\/strong\u003e Plastic\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMounting:\u003c\/strong\u003e Hull-mounted, fastens as a complete unit from either inside or outside the hull\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eHose Connection:\u003c\/strong\u003e Ventilation hose twists into the bottom of the box (hose not included)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCertification:\u003c\/strong\u003e Meets ABYC H-2 cross sectional area requirements\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eUPC:\u003c\/strong\u003e 022697664006\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eFrequently Asked Questions\u003c\/h3\u003e\u003cp\u003e\u003cstrong\u003eWhat size opening does the attwood 66400-3 clamshell vent have?\u003c\/strong\u003e The attwood 66400-3 has a 2-3\/16 inch opening and is classified as a Large size clamshell vent.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eDoes the 66400-3 vent come with a hose?\u003c\/strong\u003e No, the ventilation hose is not included with the attwood 66400-3 clamshell vent; the hose twists into the bottom of the box separately.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eCan this vent be mounted from outside the hull only?\u003c\/strong\u003e No, the attwood 66400-3 is designed to install as a complete unit by fastening from either inside or outside the hull, giving flexibility depending on the installation location.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eIs the attwood clamshell vent suitable for both intake and exhaust ventilation?\u003c\/strong\u003e Yes, the 66400-3 clamshell vent is designed for either intake or exhaust use and meets ABYC H-2 cross sectional area requirements.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat material is the attwood 66400-3 vent made from?\u003c\/strong\u003e It is made from plastic that is corrosion-resistant and will not discolor over time, suited to the marine environment.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eHow much does the attwood 66400-3 vent weigh?\u003c\/strong\u003e This clamshell vent weighs 0.0908 pounds.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat are the dimensions of the attwood clamshell vent?\u003c\/strong\u003e The attwood 66400-3 measures 0.75 inches high by 4 inches wide by 5.75 inches long.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eDoes the clamshell design help keep water out?\u003c\/strong\u003e Yes, the hose connection on the 66400-3 forms a raised water barrier at the bottom of the box when the ventilation hose is twisted into place, helping block water while allowing air to pass.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWill the attwood 66400-3 vent discolor in sunlight or saltwater exposure?\u003c\/strong\u003e No, the plastic construction is corrosion-resistant and designed not to discolor.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eIs the attwood 66400-3 vent compliant with marine ventilation standards?\u003c\/strong\u003e Yes, it meets ABYC H-2 cross sectional area requirements for marine ventilation.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat is the part number for this attwood clamshell vent?\u003c\/strong\u003e The part number is 66400-3, a Large size clamshell vent with a 2-3\/16 inch opening.\u003c\/p\u003e","brand":"Attwood","offers":[{"title":"Default Title","offer_id":48989672669403,"sku":"ATT-66400-3","price":8.03,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0839\/7586\/4539\/files\/Attwood_Stainless_Steel_Clamshell_Vent__29909.1722496039.500.750.jpg?v=1785188239","url":"https:\/\/www.goodvibesmarina.com\/products\/attwood-66400-3-clamshell-vent-2-3-16-in-corrosion-resistant-plastic-hull-vent-for-intake-or-exhaust","provider":"Good Vibes Marina","version":"1.0","type":"link"}