Features: How to use and product efficacy Efficiently provide the widest range of inspiratory and expiratory resistance levels to meet anyone's needs. From the shaking resistance to respiratory rehabilitation patients, it gradually increases to the high resistance level of competitive athletes. Improve endurance, breath holding and shortness of breath. Easy to use, only one moving part How to use the lung exerciser: The user breathes through a breathing training deviceWhen exhaling, use the force of the diaphragm to inhale and expel the air Find a resistance level that allows you to breathe in by yourself while exhaling. Repeat a few times, then rest Repeat 4-5 times a week How to use when inhaling Inhalation uses muscle rib strength and maintains muscle strength to inhale air. Inhale as deeply as possible. Breathe as long as possible. Because you breathe deeply, you will never be deprived of oxygen. More than just natural deep breathing, the end result is reduced stress and anxiety.