Marshall Excelsior MER426-15P Pigtail 15" W/Acme Connector & Marshall Excelsior RV Thermo Pigtail (Type I Acme) The RV Thermo Pigtail provides a safe, user-friendly connection from your Marshall Excelsior MEGR-9984 (#57498, 57499) regulator to a standard LP gas cylinder without the use of a wrench The easy to tighten nylon nut swivels on a connector fitting that is heat sensitive Between 240 degrees Fahrenheit and 300 degrees Fahrenheit the brass nipple displaces (approximetly 1/4 inch) closing the cylinder valve module and stopping the flow of gas from the container Inside the brass nipple is a flow-limiting device designed to sense excess gas flow If excessive gas flow is detected, the RV Thermo Pigtail will shut down the flow to a maximum of 10 SCFH (by-pass flow); 1/4 inch Male Pipe Thread x 15 inch HP hose