The Medicator® Maximizer Plus system is based upon a patented device and design that incorporates an expandable reservoir bag and a zero resistance air flow control mechanism, assembled so that the aerosol generated during the time of patient exhalation is retained in the reservoir bag and is inhaled during the subsequent breath. This results in a 2-3 times greater amount of drug inhaled by the patient. Because of the built-in exhalation port filter, the therapist is protected from breathing medicated aerosols and patient-exhaled particles.