Features It works your breathing and strengthens your abdominal muscles, which increases lung capacity, helping you improve your exercise endurance and overall performance. Its resistance is adjustable by rotating the valve to meet different exercise needs. Small size, light weight, easy to carry, can be used anytime and anywhere. Made of silicone and ABS, it is wear-resistant, tear-resistant and has a long service life. Suitable for athletes, singers, smokers, people with lung diseases, etc. Specification Colour: black&white Material: silicone+ABS Size: 5*10cm Package Included: .
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