• Food grade high quality silicone material very safety, soft and comfortable
• Designed for boosting your stamina and improve lung capacity respiratory breathing exerciser
• Also help to strengthening respiratory muscles abs easily and quickly increase your breath endurance.
• Help you to inhale more volume of into your lungs and to exhale more carbon dioxide out.
• Adjustable resistance dial allows you to adjust resistance according to your own physical condition

1 Piece Breathing Exerciser Mouthpiece