Voldyne Incentive Spirometer 2 500 mL * Volume measurement designed to accommodate large inspired volumes * Particulate filter screen in device housing helps reduce risk of foreign matter passing to patients * Expandable and collapsible tube helps patients find comfortable position for treatments and can be removed when storing the device * Ergonomic swiveled mouthpiece allows to patients create tight seal to enable more accurate measurement * Flow indicator with smiley face provides visual target for desired inhalation and bright green flow indicator make it easy for patients to see results