Portable Finger Oximeter, Measuring Instrument Equipment Saturometer Automatic Shut-Down LED Finger Pulse Oximeter Health Heart Rate Monitor Automatic power-off: Automatically power off when no signal, in the oximeter for more than 8 seconds Display: LED two-color display, waveform display SpO2 :Measurement range: 70~99 %;Resolution: ± 1%;Accuracy: ± 2% (70%~99% Pulse http://rate:Measurement range: 30~240 bpm;Resolution: ±1 %;Accuracy: ±2bpm or ± 2% (select larger) ;Low Perfusion ≤ 0.4% Please replace new batteries when LED indicates the batteries are in low power.