Feature:1. Improve Endurance: Using a breathing trainer can improve the strength and endurance of the respiratory muscles, fatigue of the respiratory muscles is a limiting factor in exercise, strengthening the respiratory muscles can improve the limits of exercise.2. Increase Respiratory Strength: Enhance respiratory strength and control performance. Training your anaerobic broadening and push your limits. Increase oxygen intake and maintain endurance.3. Easy to Perform: Inhale slowly and as deeply as possible through your mouth and hold your breath for a few seconds. Exhale slowly through your mouth until you are almost completely out of breath. Then repeat the above exercise 10 to 15 times to complete the set. Do 2 to 4 sets per day.4. Lung Capacity : It helps to expand and improve your lung capacity without the danger of doing a lot of cardio and burning calories.5. Portable Device: The lung breathing trainer is very small and portable. With this device, you can perform your training routine wherever you are.How to Use:Insert the mouthpiece into the mouth, bite the inside of the mouth and fix it in the proper position of the throat and tongue. Inhale and exhale during adjustmentThe resistance valve selects the level of breathing resistance you want (make it challenging, but not uncomfortable). Turn the valve to the left for more resistance (+) and to the right for less (‑).Specification:Item Type: Breathing Exercise DeviceMaterial: Silicone, ABSColor: Black and whitePackage List:1 x Brea