Fingertip Pulse Oximeter GMT-504 Features The device can accurately measure SpO2 and pulse rate in a ?% tolerance. The device will power off automatically without the signal for 4 seconds. Two AAA size batteries are required for operating, and the continuous working time is 12 hours . When Low-Voltage Warning is shown on screen and the malfunction may be caused . The device is so light that its weight with batteries is about 50g . Specification A. Display mode :LCD Display SpO2 display: 50%~99% , 2-digit and 7-segment digital display Pulse rate display : 30bpm～240bpm, 3-digit and 7-segment digital display Pulse wave’s intensity display: 6-segment bar-graph display Low Battery voltage indication: Segment LCD Signal B. Power supply requirement: 1.5V ( AAA size ) alkaline battery ?2 Battery voltage : 2.6V~3.3V C. Operating current: < 10mA D. Resolution: SpO2 1% Pulse Rate 1bpm E. Accuracy: SpO2 ?% ( during 80%～99%) SpO2 ?% ( during 70%～79% ) Pulse Rate 2bpm F. Measurement at low perfusion: The values of SpO2 and pulse rate can be displayed properly when pulse saturation is at 0.5% . G. Resistance to surrounding light: The difference between the value measured in the condition of indoor natural light and that of darkroom is less than ?%. H. Resistance to interference of man-made light: Values of SpO2 and Pulse Rate can be accurately measured by pulse oxygen simulator. I. Automatic shutdown function: The device will power off automatically in 4 seconds when there is no finger in the device. Dimension: 58(L) ?32(W) ?34(H) mm Weight: 50g (including 1.5V (AAA size) alkaline batteries ?2) Environment requirements: Temperature: Operating Temperature: 10癈 ~40癈 Storage Temperature: -20癈~55癈 Humidity: Operating Humidity: 35%~80% Storage Humidity: 10%~100% Atmospheric pressure: Operating Pressure: 70kPa~106kPa Storage Pressure: 50kPa~106kPa