Features: Respiratory muscle trainers considers it a lung fitness center. It is a good product to improve aerobic exercise endurances, improve Lung capacity, improve muscle endurances, reduce dyspnea, improve sleep quality and exercise lungs and respiratory muscles. Use: The breathing trainers can adjust the size of your breathing resistances. You can adjust the resistances by turning the valves ť to improve your daily breathing health, increase endurances and Lung capacity. Widely applicable to various places such as swimming, diving, surfing, running, fitness, tourism, etc. Preferred material: Made of high-quality silicone material, with good adhesion and sealing properties; Environmentally friendly and completely safe. Notice: 1.Actual color may be slightly different from the image due to different light effect 2.Please allow 1-3cm deviation due to manual measurement Description: Material: SiliconeABS Size: 5*10cm Package List: 1X Breathe-Exercise Device