A suction device is a tool used to create a vacuum in order to move liquid or gas from one place to another. The term 'suction device' can refer to a variety of tools, including a SIPHON, which is a device that uses gravity and atmospheric pressure to move liquid or gas from one container to another. A SIPHON is composed of two tubes, one of which is placed lower than the other, allowing the liquid or gas to flow from the higher tube to the lower tube.