Bronze Vented Loop – 1-1/2″ HoseFeatures:Allows air to enter to break siphon, but does not permit air and odors to escape! Cap is threaded 1/2″ NPT to accept a barb fitting if you wish to vent overboard.Overboard venting is required if PVL or HVL series is used in an exhaust system.HVL and PVL series vented loops assure clog-free anti-siphon protection for sanitation or engine exhaust systems. The oversized vent valve can easily be removed for inspection or cleaning without tools.Mount Hardware is included. Specifications:Type: Vented LoopsBox Dimensions: 3″H x 7″W x 8″L WT: 2.55 lbsUPC: 742985002715