The present invention utilizes high magnetic flux materials to substantially increase the power which can be transmitted from a magnetic driver, disposed outside of a vessel containing a fluid being processed, to a magnetically responsive agitator means disposed inside the vessel. This invention now enables the agitation, e.g., mixing, blending, etc., of fluids processed in the pharmaceutical, chemical and food processing industries, where relatively high torques are encountered, by non-contaminating magnetic drive means heretofore precluded in such applications. Means for producing vibrational agitation, and for reducing wear of the internal agitator bearing are also disclosed.