This handheld spirometer by AirLife, model number 001901A, is a must-have for anyone in need of measuring their lung capacity. It features a volumetric incentive design with a one-way valve, allowing for accurate readings up to 4000 mL. Perfect for medical and laboratory professionals, this spirometer is ideal for use in hospitals, clinics, and even at home. The compact size and easy-to-use design make it convenient for anyone to measure their lung function. Don't miss out on the opportunity to improve your respiratory health with the AirLife Volumetric Incentive Spirometer.