The pulse oximeter is used to indirectly measure the functional oxygen saturation (SpO2) of a patient's blood. Pulse oximetry combines the principles of optical plethysmography and spectrophotometry to determine arterial oxygen saturation values. Pulse oximetry is a critical factor in vital signs measurement and monitoring. Masimo SpO2 sensors facilitate easy, comfortable, accurate pulse oximetry measurement. The sensor clips painlessly onto a patient's finger and connect to pulse oximeters and vital signs monitors with its 3' cord and 9-pin connector. For adults weighing 66 pounds or more.