An agitator is a device or mechanism used to put something into motion by shaking or stirring. In general, agitators usually consist of an impeller and a shaft. An impeller is a rotor located within a tube or conduit attached to the shaft. Agitators are used to mix liquids or products together or to prevent congealing. A shaft is a rotating machine element, usually circular in cross section, which is used to transmit power from one part to another, or from a machine which produces power to a machine which absorbs power. The various members such as pulleys and gears are mounted on it. Specifications. Height 3.8 in.. Width 4 in.. Length 18.3 in.