Feature: 1. 1. Airway muscle trainer, treat the airway trainer as a lung fitness center. Exercise the lungs and respiratory muscles to improve lung capacity and endurance. 2. 2. Improve sports performance and daily breathing health. Breath trainers can adjust the amount of air you take in, improve your daily breathing health, and increase endurance and vital capacity. 3. 3. The breathing exerciser uses a multi-level resistance dial to reduce the amount of air flowing through the lungs, forcing you to breathe more concentrated and deeper. 4. 4. Most effective to improve durability, keep breathing. 5. 5. Provides 100% adjustable inhalation and exhalation resistance. Specification: Name: Breathing Exercise Device Material: Silicone Size: One size Color: As shown Package List: 1 x Breathing Exercise Device Note: 1. For photos, please allow slight color difference. 2. Due to manual measurement, the size may vary.