features：
▪ display: oled screen
▪ direction: four directions display
▪ accuracy: spo2: 70%~100%, ±2%
pulse rate: 30~99bpm,±2bpm; 100~250bpm,±2bpm
perfusion index: 0.2~1.0%,±0.2digits; 1.1~20.0% ,±20%
▪ battery: aaax2
▪ dimensions: 62.2x37.0x33.1mm
▪ weight(without batteries): 28.6g
▪ parameters: pulse rate,spo2,pi(perfusion index)
▪ indication: real-time battery statues,weak or unstable signal,
value limit remind
▪ application range: adult,adolescent,child