PCUpgraded Durable PC MaterialConstructed with high-quality PC material, this breathing exercise device for lungs is incredibly durable and shatterproof. Unlike other models made from fragile materials, this device withstands heavy use without breaking. The clear markings make it easy to read and track progress.Incentive Spirometer AdultEasy to Use with Leading 5000ml Capacity: This Incentive Spirometer combines an integrated molding design for cleaner breaths with a remarkable 5000ml (5 liters) capacity. This extensive range(clear matched from 500-5000ml) allows for precise capacity measurement and evaluation.Airflow Indicator for Controlled BreathingFlow Rate Indicator& Precise Control: Our distinct flow rate ball can guide your breathing. If the yellow ball rises above the upper limit, you are inhaling too quickly; if it stays below the lower limit, you are inhaling too slowly. Aim to keep the indicator at the smile face in middle positio for optimal breathe level.Detachable Design: The flexible tube and mouthpiece design allow for easy adjustment in various positions. After use, they are easy to clean, and the device includes built-in storage space for convenient organization. The removable tube and mouthpiece also easy clean after use and good for hygienic maintenance.Easy to useWe have instructions for use It is not difficult to use, the colored balls are relatively interesting, and can be used by all ages,incentive spirometer Lightweight, easy to carry, can also be used when going out, which is conducive to long-term persistence.