Flame King (KT12ACR6) 2-Stage Auto Changeover Propane Gas Regulator with 2 12" Pigtails 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 Inlets are 1/4" SAE inverted flare and outlet is 3/8" NPT female pipe thread. Rated for 30,000 BTU Double stage design maintains constant gas pressure under changing demand and conditions Includes 2 12" pigtail hoses to connect to the propane tank