Assemblies: Pump: 5: 1 Bung adapter: fix the pump with the drum Rigid connector Flow meter gun ( art 37713) It uses compressed air as its power, forces the pump move to and fro, then deliver the liquids through connecting the hose reel with the flow meter gun. It is adaptable for 180-220L drum. It is the first choice for automobile amendment, auto 4s station, gas station, and working line.