Cytoplasmic ring located at the base of the bacterial-type flagellar basal body; acts as a rotor; includes three switch proteins, which generate torque and can change their conformational state in a bimodal fashion, so that the motor direction can switch between clockwise and counterclockwise. [ http://www.ncbi.nlm.nih.gov/pubmed/10572114 http://www.ncbi.nlm.nih.gov/pubmed/12624192 ]