A reliable, code-compliant connection between your RV propane cylinder and your regulator. The built-in back check valve prevents hazardous backflow when swapping tanks in a dual-supply setup -- a critical safety feature many bare pigtails omit. RV Type 1 (ACME) tank fitting on one end, standard 1/4" male inverted flare on the regulator side.
The MB Sturgis 100575-48-MBS is a 48-inch (4-foot) propane pigtail hose designed specifically for RV applications where a dual-cylinder automatic changeover regulator or a manual two-stage regulator is used. The extra length compared to a standard 12" or 24" pigtail gives you comfortable slack to connect cylinders stored in an outside compartment without straining fittings or kinking the hose.
The defining feature of this pigtail is the integrated back check valve at the Type 1 ACME end. In a dual-tank setup, if one cylinder is removed while the other is still supplying gas, the back check prevents propane from escaping through the open fitting -- reducing the risk of a gas release during tank swaps. This makes the 100575-48-MBS a preferred choice over plain pigtails wherever dual-tank operation is the norm.
Prevents backflow and gas escape during tank swaps in dual-cylinder setups. Not just a convenience -- a safety requirement on many rigs.
Handles the full demand of virtually any RV appliance load -- furnace, range, water heater, and refrigerator running simultaneously.
Threads onto standard POL-to-ACME adapter valves found on most portable propane cylinders (20 lb, 30 lb, 40 lb) used on RVs.
The industry-standard connection for most two-stage and automatic changeover RV propane regulators. No adapter needed in typical installs.
Tank end -- RV Type 1 (ACME): The Type 1 connector is a left-hand-threaded ACME fitting (approx. 1-5/16"-18 ACME threads) that screws directly onto the OPD (Overfill Protection Device) valve of modern DOT propane cylinders. This is the same fitting style used on BBQ grills and most recreational cylinders sold in North America. Tighten by hand plus a quarter-turn with a wrench -- do not overtighten, as the ACME thread is designed for frequent connect/disconnect cycles.
Regulator end -- 1/4" male inverted flare (MIF): Connects to the female inverted flare inlet on most standard RV automatic changeover regulators and two-stage regulators. This is the dominant thread standard for propane supply lines in recreational vehicle applications. Thread direction is right-hand (standard). Use thread sealant rated for LP gas or an appropriate lead-free compound if required by local code -- do not use Teflon tape on flare fittings.
Automatic changeover regulators are designed to draw from one cylinder at a time. When the active cylinder empties, the regulator switches to the reserve. If you disconnect the empty cylinder while the system is pressurized, a plain pigtail allows propane to flow backward out of the open fitting. The back check valve in the 100575-48-MBS closes automatically when the tank is disconnected, isolating the regulator side and preventing gas release. This is why NFPA 58 and most RV manufacturer service manuals specify back-check pigtails for dual-cylinder installations.
MB Sturgis makes this pigtail in multiple lengths. The 48" (4 ft) version -- part 100575-48-MBS -- is the longest in the standard series and works well when the regulator is mounted away from the cylinder compartment, or when the compartment is deep and a shorter hose would be taut. If your cylinder-to-regulator distance is short (12" or less), a 24" or shorter pigtail reduces the chance of hose contact with hot components. Match length to your installation, not just availability.