A hand-held instrument designed to measure the maximum rate of oral or nasal inspiratory gas flow [peak inspiratory flow (PIF) or peak inspiratory flow rate (PIFR)] into the lungs, to assess airway patency. It is in the form of a cylinder with a mouthpiece for inhalation and a calibrated analogue scale that shows the peak flow value; a nasal mask may be attached to the device for evaluating nasal airway patency. It is used during pulmonary function testing as an alternative to rhinomanometry to help diagnose respiratory disorders [e.g., allergic rhinitis, chronic obstructive pulmonary disease (COPD)], or to assess/train medication inhalation technique. This is a reusable device.