ENHANCE ATHLETIC PERFORMANCE & EVERYDAY RESPIRATORY WELLNESS HOW IT WORKS: The Adurance Breathing Trainer regulates how much air you take in, improving your everyday breathing wellness along with increasing your stamina and lung capacity. The Breathing Trainer uses a multi-level resistance dial which reduces the amount of air flow to the lungs, forcing you to take more focused and deeper breaths. The lungs are pushed to work tiny air sacs in your lungs called "alveoli" harder, which improves blood and oxygen flow. Breathing training against resistance will increase and condition lung capacity and improve your overall performance in sports and everyday activities. Our Breathing Trainer can give you a substantial improvement in shortness of breath and endurance, all done naturally, through better breathing. Experience less fatigue, improved stamina, and unmatched endurance! Comfortable, portable and easy to use, the Adurance Breathing Trainer is the ultimate secret weapon to enhance your performance!