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. Specifications. Height 1.35 in.. Width 7.9 in.. Length 1.9 in.