The SPIROMETER is a hand-held equipment for checking lung conditions, adopts the infrared signal acquisition mode for measuring items related to FVC, and it is applicable for hospital, clinic, family for routine test. Functions 1) Forced Vital Capacity (FVC), forced expiratory volume in one second (FEV1) to forced vital capacity (FVC) ratio (FEV1/FVC), peak expiratory flow (PEF), forced expiratory flow at 25 % of FVC (FEF25), forced expiratory flow at 50 % of FVC (FEF50), forced expiratory flow at 75 % of FVC (FEF75) and forced expiratory flow from 25 % ~ 75 % of FVC (FEF2575) can be measured? 2) The personnel information (including height, age, sex, etc.) can be set. 3) Flow - volume chart, volume - time chart display. 4) The data can be stored, deleted, uploaded and reviewed. 5) Trend chart display. 6) Health state indication. 7) Calibration function. 8) Over - limit prompt function for volume and flow. 9) Bluetooth transmission. 10) Real-time clock can be set and displayed. 11) Battery power indication. 12) Automatic shutdown when there is no operation within two minutes. Performance ? Display mode: 2.4'' LCD ? Volume range: 0 ~ 10 L ? Volume accuracy: 3 % or 0.05 L (whichever is greater) ? Flow range: 0 L/s ~16 L/s ? Flow accuracy: 5 % or 0.2 L/s (whichever is greater) ? Working current: 200 mA ? Power supply: two AAA batteries ? Safety class: internally powered equipment, type BF applied part Accessories 1) One User Manual 2) One mouthpiece (disposable accessory) 3) One nose clip (optional) Physical characteristic Dimension: 138 mm (L) 63 mm (W) 47 mm (H) Weight: 150 g (including battery)