Wellue Pulse Oximeter Fingertip Blood Oxygen Saturation Monitor with Batteries & Lanyard for Wellness Use FS20F BluetoothACCURATE AND RELIABLE: 20% OFF. Accurately measures your blood oxygen saturation levels(SpO2 ), pulse rate, pulse strength and pulse waveform and display them conveniently on a large OLED screen.WARNINGS FOR ABNORMAL READINGS: The value on screen will flash when abnormal SpO..