XiXi Shop Item Type: Lung Exerciser Expander DeviceMaterial: Silicone, ABSGross Weight: 75g / 2.6ozProduct Size: Approx.5 x 10cm / 2.0 x 3.9in { font-family:'Arial' important; } table { border-top: 1px solid 000; border-left: 1px solid 000; } table td, table th { border-bottom: 1px solid 000; border-right: 1px solid 000; padding: 3px 5px; } table th { text-align: center; } 1Endurance Improvement: Breathing muscle trainer, improve aerobic exercise endurance, and enhance muscle endurance. 2Increase Lung Capacity: This lung exercise dilator can help you adjust your breathing and increase vital capacity during exercise. 3Improve Physical Function: This breathing trainer can help improve shortness of breath and palpitations, and improve physical function. 4Adjustable Resistance: This lung capacity training device can adjust the resistance according to the needs, and it is easy to use. 5Portable: This breathing training device is easy to carry, compact, lightweight, easy to clean, and no burden for sports.