Designed specifically for the Adult and Jr Swimmer's Snorkel, the Snorkel Cardio Cap can be used for hypoxic training, which increases the ability of muscles to work better when oxygen levels are low. The Snorkel Cardio Cap replicates higher altitude workouts. The Snorkel Cardio Cap improves breathing by teaching a deeper technique for high anxiety and race day environment. Using the Snorkel Cardio Cap is also a great way to strengthen intercostal muscles through forced inhalation and exhalation.