... display,resolution 160*64SPO2:35-99% Pulse Ratio:30-250BPMResolution:1% for SPO2,1BPM for pulse ratioAccuracy:±2% (70%-99%),unspecified(<70 ... %)for SPO2,±2BPM or ±2%(select larger)for pulse ratioPower:1.5V(AAA size)alkaline batteries x2Can work more ... ambient light and measurement performance at low perfusion FDA approved pulse oximeter with LED display