A Finger pulse oximeter Spo2 or a Blood Oxygen Saturation Monitor is a small, lightweight device used to monitor the amount of oxygen carried in the body. This blood oxygen monitor attaches painlessly to your fingertip, sending two wavelengths of light through the finger to measure your pulse rate and your Blood Oxygen Saturation. Once the finger pulse oximeter Spo2 and the Blood Oxygen Saturation Monitor  finishes its assessment, the screen of the finger pulse oximeter will display the percent of oxygen in your blood coming from your heart—as well as your current pulse rate.