 The modern agitator, which is dual-action, was first made in Kenmore Appliances washing machines in the 1980s to present.These agitators are known by the company as dual-rollover and triple-rollover action agitators.This is a device formed by a metallic bar (called the agitation bar) which is normally covered by a plastic layer, and a sheet that has underneath it a rotatory magnet or a series of electromagnets arranged in a circular form to create a magnetic rotatory field.