Perko Vented Flip Top Cap f/Fills with 1-1/2" HoseBlack PolymerEasily Mounts Directly on Gunnel with Removing Fill BodyIncludes Metallic Inserts for Gas, Diesel or Water FillsIntegral Tank Vent with Flame ArrestorNo Deck Plate Key or Ground Wire RequiredFlip Top CapTechnical InformationRequires 5-1/4" DiameterMounting Surface Screw Size: #8