This unique and easy-to-use FINIS Cardio Cap For Hypoxic Lung Training is designed to fit on top of the FINIS Front-Mounted Swimming Snorkel to increase the conditioning and work load of your lungs by 40%. This is a perfect “hypoxic” swim training tool, and the benefits of hypoxia include stronger lungs and inspiratory and expiratory muscles, increased growth hormone, increased DHEA (an anabolic, muscle-building, fat-burning hormone), better performance at high intensities, and much more!