An open bite is one of the most difficult malocclusions the clinician has to deal with. In recent years, interest has increased regarding mechanics that reduce dependency upon patient compliance for success. Some patient-independent mechanism for molar intrusion or vertical control is desirable. The rapid molar intruder (RMI) appliance consists of two elastic modules that are secured to orthodontic bands on the upper and lower first molars. Vertical forces from these modules typically produce intrusion of the permanent molars in four to six months. The RMI modules may be used in the mixed dentition or incorporated in full-fixed mechanics in the permanent dentition. To avoid buccal flaring of the molars, these modules should be attached to a transpalatal arch and a mandibular lingual arch. Case reports are provided to stimulate interest in further investigation of the properties of this appliance.