Extend-A-Stay kit allows you to hook up the RV to outside "satellite" propane cylinders. Special tee fitting allows the RV's LP gas system to run off an outside LP tank through a 5' pigtail. Also runs high-pressure appliances with included 12' male X female hose. Look under the category of "LP Tanks" for the 7-1/2 gallon tanks commonly used in this hook-up.