Features: By vibrating and movings, it helps to clear mucus from the pulmonary valvesand promotes respiratory health. By using this device for lung breathing exercises, lung function can be enhanced and respiratory capacity can be improved. Equipped with three steel ball, it produces a vibrations effect, stimulates sputum excretion in the lungs, and accelerates the removal of mucus. According to personal needs, the vibrations intensity and frequency of the device can be adjusted to gradually increase the difficulty of training. Suitable for people who are concerned about respiratory health and hope to improve lung conditions and reduce sputum accumulation. Specifications: Material: Plastic and Steel Ball Color: White/Blue Length: Approx. 10cm/3.94inch Package Includes: 1set Lung Exerciser Device note: Please allow 1-2cm errors due to manual measurement, make sure that you do not mind before you order. Due to the difference between different monitors, the picture may not reflect the actual color of the item.