*Experience a new level of endurance !* Use during athletic training or as a stand alone breathing exercise . Strengthen your lungs & diaphragm, increase airflow, be ready to perform at any altitude. DESIGNED FOR EVERYONE AT ANY PERFORMANCE LEVEL! Engineered to increase inspiratory (inhalation) muscle endurance, the O2 Trainer is lightweight and designed to be used while performing nearly any exercise or activity. Whether you're running, weight lifting, or rock climbing, the O2 Trainer will train your lungs and body to perform at high levels with less oxygen, and teach them to maximize every breath.