Specifically designed to meet the high demands of today’s motorhomes, trailers and on demand hot water heaters. The new High Flow pigtails are designed with both excess flow and thermal link safety features, same as the green nut Type I. The RV Thermo Pigtail (Type I ACME) provides a safe, user-friendly connection from your Marshall Excelsior 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. 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 (by-pass flow). This product is required by RVIA (Recreational Vehicle Industry Association) as original equipment on your RV and should be maintained to the highest standards. Because of this required standard, when opening or refilling your LP gas cylinders, it could take as long as 20 Minutes to re-pressurize your LP gas system for normal appliance(s) operation.