... 4 directions, 8 display Finger Pulse Oximeter with CE approvedFunction:1,Monitoring pulse, SpO2,PR(Pulse Rate).2,Displaying volume ... Oximeter (it is best to plug the finger thoroughly) before releasing the clamp4 Press the ... button once on front panel.5 Your finger do not tremble during the Oximeter is working ... rate bargraph display corresponds with pulse rate. Finger Pulse Oximeter with CE approved