Figure 26-2 Three hand-held peak flow meters. The classic Wright meter (Air Med Limited, Harlow, England) and the Assess peak flow meter (Health Scan Products, Cedar Grove, NJ) quantitate the peak flow rate. The smaller peak flow monitor (Biotrine Corporation, Woburn, MA) allows the patient to tape over the holes before blowing. If the flow rate indicated by the first uncovered hole is reached, a hornlike sound is produced by a metal, reedlike device within the tube.