Outdoor Retailer Snow Show Innovation Award Winner! One Gas Growler fill costs about the same as one single-use green bottle 5 times as long.Includes a 4/1.2M that attaches to all heaters and stoves that use single-use green propane bottles. The Gas Growler complies with DOT specifications 4BA 4BW and 4E.It is safe to transport in your car SUV RV or boat. Rugged protective case with room for hose and wrench storage. Stitched webbing for attaching pouches for accessories or strapping down for transport. Tanks are shipped pre-purged and ready to be filled at any propane filling station.