Pulse oximeter is a non-invasive portable device that monitors the oxygen saturation of arterial hemoglobin (SpO2) and pulse. The oximeter is suitable for adults and children. The technology of pulse oximetry uses the absorption of light by hemoglobin and the pulsatile flow of blood in the arteries. The pulse oximeter uses a sensor that emits light at two wavelengths, red and infrared, to a part of the body that is relatively thin and has good arterial pulsatile blood flow, usually the finger or earlobe. It features a light detector which, together with a microprocessor, compares and calculates the differences between oxygen-rich hemoglobin and oxygen-poor hemoglobin.