Features:Respiratory muscle trainers considers it a lung fitness center. It is a good product to improve aerobic exercise endurances, improve Lungcapacity, 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 + to improve your daily breathing health, increase endurances and Lungcapacity.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.Service:If you have any question,please contact us to provide great service.Notice:1.Actual color may be slightly different from the image due to differentlight effect2.Please allow 1-3cm deviation due to manual measurementDescription:Material:Silicone+ABSSize:62cm *35cm *33cm