Chronic Obstructive Pulmonary Disease (COPD) is a chronic disease that leads to irreversible changes in the lung structure, but also to systemic changes in the body that can influence the severity of the disease. The irreversible changes to the lungs can be seen in limitations in the pulmonary function. The purpose of this clinical investigation is to evaluate the performance and efficacy of the ROX AC1 on exercise capacity and respiratory quality of life.