Marshall Excelsior MER426-20P Pigtail 20" 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 This product is required by RVIA (Recreational Vehicle Industry Association) as original equipment on your RV and should be maintained to the highest standards. 1/4 inch Male Pipe Thread x 20 Inch HP hose,