 The objective of this study is to evaluate the safety and efficacy of four times daily oPEP use over 4 weeks in individuals with stable COPD. The oPEP device combines positive expiratory pressure therapy and airway vibrations to help mobilize pulmonary secretions. oPEP therapy enforces a resistance to exhalation at the mouth while the airway vibration technology transmits movements upstream during exhalation so that airway walls may become free from mucus. An adjustable dial allows users to adjust the frequency and the flow resistance based on their individual needs. Subjects will take a device home and use four times daily during the active part of the study. We hypothesize that daily Aerobika use will significantly improve St. Georges Respiratory Questionnaire SGRQ score, six-minute walk distance 6MWD and forced expiratory volume in one second FEV1 after four weeks of four times daily administration. 