The high quality plastic material is nontoxic, odorless and environmental.
Small size and lightweight, you can keep it with you all the time and have a breathing training whenever you want.
You can gradually increase your vital capacity with a continuing breathing training, keep it in your mouth when you are doing anaerobic sports like jogging, swimming and cycling.
Easy to use
Just clench it in your mouth and normally breathe, it will be better if you do it when you are having sport activities.
Your jaw muscle may be strengthened after a long-term use, because you need to clench it with your teeth in order not to let it go out of your mouth.
Item type: Breathing Trainer
Color: black and white
Item size: 5*10cm/1.97*3.93inch(W*H)