Using ultrasonic time difference, by measuring the co-current and countercurrent time difference ,the spirometer determine the volume of gas flow, getting spirometric parameters from respiratory flow curve .
By computer processing system, measuring expiratory function and inhale function of the human body through gas flow sensor , the display shows real-time breathing curve and calculate various indicators parameter.The human body can be used for static vital capacity, forced vital capacity, maximum voluntary ventilation plus measured
Spirometer can be used to measure static vital capacity, forced vital capacity, maximum voluntary ventilation .
Different regions of predicted value based on lung function related factors (height, weight, age), establish database for user to query history test results ,providing the basis for tracking contrast diagnosis .
The software automatically do BTPS correction, evaluate pulmonary function automatically . 
No need to replace the sensor, no maintenance, simple, lightweight, easy to carry .
Disposable mouthpiece, the type suitable for children and adults .