1.peak flow meter, Peak Expiratory Flow (PEF) and FEV1 2.measurement 3.High accuracy 4.Rotating vane wheel method peak flow meterPeak Expiratory Flow (PEF) and FEV1 measurement High accuracy Rotating vane wheel method Suitable for children and adults 240 data memory Traffic light indicator Professional carrying bag Battery driven Equipped with wall holder Software and connection cable included