Allows removal of empty cylinder for refill without interrupting propane supply For RVs with dual propane tanks; Automatically switches from primary to reserve tank when primary is empty Pairs well with our 48 Inch Thermo Plastic Hose, item 100383-48. Double stage design maintains constant gas pressure under changing demand and conditions Inlets are 1/4" SAE inverted flare and outlet is 3/8" NPT female pipe thread. Regulator is factory set at 11wc (water column) Rated for 190, 000 BTU