Squeeze the hand pump to initiate the siphon to start transferring liquid from one receptacle to another. You can easily empty containers with the Liquid Transfer Pump. This gas siphon pump has an air valve at the top to stop the flow of liquid. Suction tube reaches 16" below pail lid. The Tube can be trimmed to fit any container. This manual siphon pump is used to transfer water, oil or other liquids quickly and easily. Can be used to remove water from clogged sinks, waterbeds, broken wash machines, boat and pool covers.