TRAININGMASK Training Mask 2.0 Gym Workout Mask – for Cardio Stamina, Running, Endurance and Breathing Performance [Official Training Mask Used by The Pros}

TrainingMask Original’s multi-level resistance loads the respiratory muscles by adding friction to inhaled air through its patented flux valve system More respiratory power and stronger breathing muscles will supercharge your stamina and endurance.TrainingMask Original’s multi-patented flux valve technology offers six levels of resistance which allows you to work on breathing power, inspiratory muscle strength, and breathing technique.The lightweight and comfortable design of TrainingMask Original makes it a perfect addition to most forms of exercise from strength workouts to cardiovascular training.'