This fingertip pulse oximeter is compact and light in weight, easy to use with only one-key operation. The internal alarm will function while low voltage. Automatically power off after 8 seconds when finger out. The continuous working time can be 39 hours. LED monitor for extended battery life SpO2 and pulse monitoring, and histogram of pulse display Easy to use with one-key operation Small in size, and easy to carry Low voltage alarm display Auto power-off after 8 seconds without signal Light weight of 50g, batteries included Runs on standard AAA batteries and continuous working time is 39 hours Display Format: LED SPO2:35-99% in two-digit 7-segment digital Pulse Ratio:30-240BPM in 3-digit 7-segment digital; Pulse Wave: 6-segment barograph; Battery Voltage Low Indication: LED signals Dimension:58(L) í- 30(W) í- 36(H) Weight:55g (including batteries) Power Requirements: 2 AAA size 1.5V Alkaline Batteries Power Consumption: less than 40mA. Resolution: í+1% for SPO2 and í+1 BPM for Pulse Ratio. Measurement Accuracy: í+2% in stage of 70%-99% SPO2 and meaningless when stage being smaller than 70%. í+2 BPM for Pulse Ratio. Measurement Performance in Weak Filling Condition: Oxy haemoglobin and pulse value can be shown correctly when pulse-filling ratio is 0.5%.