Color OLED display with brightness adjustable, 25bpm~250bpm PR measuring range, 0%~100% SpO2 measuring range, ±1bpm or ±1% accuracy, six display modes, four-direction display, blood perfusion index (PI) as low as 0.2%, low-voltage indication, pulse sound, alarm function, auto shut off without signal after 10 second, 25mA power, AAA x 2 batteries.