In a matter of seconds, this oxygen sensor will accurately calculate your SpO2 (blood oxygen saturation levels), heart rate, and pulse strength, and display them on a large digital LED display. The monitor is very light, small in size, uses very little power, and is simple to carry with a detachable cord, allowing you to test oxygen saturation almost anywhere. The auto power off function saves battery life by turning off the device seconds after removing the finger. Two AAA batteries are needed (included). The pulse rate and spo2 blood oxygen saturation of arterial haemoglobin levels are measured rapidly and reliably by an oxygen sensor finger. Determine your spo2 (blood oxygen saturation levels) accurately, take quick spo2 readings, and test your pulse on a big digital bright led monitor. Place your finger in the pulse oximeter's rubber and click "on." Exercise rehabilitation tool for the elderly, runners, and climbers (monitor the oxygenation rate of cells, for overall health).