Reliable accuracy and durability; Two Color OLED Display four display modes; 4-Direction Display adjustable; Low voltage indicator Real-time spot-checks; Low power consumption50 hours continuous to work; Low Perfusion </= 0.4%; Automatic power off when no signal; Small and light weight convenient to carry; Widely used in hospital home healthcare oxygen bar community medical centre alpine area sports healthcare etc. Specification: Display OLED two color display; SpO2 Measurement range: 70~99%; Resolution: +/- 1%; Accuracy: +/- 2% (70%~99%) unspecified (<70%); Pulse rate: Measurement range: 30~240 bpmResolution: +/- 1%Accuracy: +/- 2bpm or +/- 2% (select larger) Low Perfusion </= 0.4%; Power: 2 x 1.5V (AAA size) alkaline batteries; Supply voltage: 2.6~3.6V; Working current: </= 30mA; Automatic power-off: Automatically power off when no signal in the oximeter for more than 8 seconds