... /box, 200pcs/carton(40*60*55,15kg) Peak Flow Meter ( medical device, medical oxygen flow meter )It is a portable, hand-held ... push air out of your lung and provide an correct indicator of the condition of airway.Material: ABSSize: (oval) 30/50 ... : 1pc/box, 200pcs/carton(40*60*55,15kg) Medical Peak Flow Meter