Size 3″. Bronze. Venting improves the efficiency of loading and unloading cargo by eliminating dangerous pressure or vacuum buildup. Inverted Vent Check Valves add a measure of security, preventing deck wash, deck fire and debris from traveling through the vent. Approved for installation aboard USCG inspected vessels. Heavy Cast Construction, with 316ss ball float. Available in bronze, galv. steel, 316SS, and 535 aluminum. Connection type – Threaded (standard). Also Available with Butt-weld or Flanged connections.