1. BREATHING EXERCISE: Breathing exercise device challenges yourself to perform the better workout and improvement of your overall stamina. 2. LUNG CAPACITY: It helps to expand and improve your lung capacity without having to do a ton of cardio and risk burning calories. 3. PORTABLE DEVICE: Lung breathing trainer is extremely compact. With this device, perform your daily training wherever you are. 4. WORKS GREAT: Adjustable resistance dial makes simplest tasks tougher and workouts more intense as your needs. How to use a lung exerciser 1. The user breathes through a breathing training device. 2. When exhaling, use the force of the diaphragm to inhale and expel the air. 3. Find a resistance that allows you to inhale by yourself while exhaling. 4. Repeat a few times and then rest. 5. Repeat 4-5 times a week. Specification: Material: Silicone, ABS. Size: 5 x 10 cm. Application: swimming training; running, cycling, etc. Package Included: 1 x Lung Exerciser.