Model Mini Spirometer, Maxiumum measurement volume 10L. Max Flow rate 16 L/s. Volume accuracy +/- 3% or 50mL. Flow accuracy 5% at 200mL/s. Power supply Built in lithium battery. Dimensions 97mm by 89mm by 36mm. Net weight 150 grams. Color LCD display. Membrane keypad. On/Off button menu selection button and two up/down navigation arrow buttons. Simple to use. Ideal for primay care, sports medicine and occupational health.