Finger tip pulse oximeters A pulse oximeter shines two beams of light through a finger (or earlobe etc.), one beam is red light (which you can see when a pulse oximeter is used), one is infrared light (which you don’t see). These two beams of light can let the pulse oximeter detect what colour the arterial blood is and it can then work out the oxygen saturation. However there are lots of other bits of a finger which will absorb light (such as venous blood, bone, skin, muscle etc.), so to work out the colour of the arterial blood a pulse oximeter looks for the slight change in the overall colour caused by a beat of the heart pushing arterial blood into the finger.
Finger tip pulse oximeter. This is first aid kit material. Medical staff and medical professionals use this model, as do medical supplies. Health products for work or home.