1?Display mode: OLED Display of the oxygen saturation : 70 ~ 100%?±2% Pulse power display: 25 - 250 BPM?±1% or ±1BPM?and take the larger one 2?Power supply: 2 AAA 1.5V alkaline batteries; Voltage suitable range: 2.6 ~ 3.6V 3?Power consumption: less than 30mA 4?Measure precision: the oxygen saturation between 70%-99%, the precision is ±2%; and less than 70% the precision has no definition; the pulse power is ±1% or ±1BPM,and take the larger one. 5?Measure capability under the situation of weak perfusion: it can rightly display the oxygen saturation and the pulse power when the pulse fullness degree is 0.6%. 6?Compared to the measure value in the darkroom, the oxygen saturation in the natural light and the illuminate light-house, the warp is less than ±1%. 7?Have function switch, and it will stop automatically after 8 seconds without finger insert in.