ROSSMAX DUAL HEAD STETHOSCOPE EB200

The peak expiratory flow (PEF), also called peak expiratory flow rate (PEFR) is a person's maximum speed of expiration, as measured with a peak flow meter, a small, hand-held device used to monitor a person's ability to breathe out air. The peak flow meter is a scientifically designed portable device to measure lung capacity or airflow in the lungs. It...