EASY TO USE: Our pulse monitor is easy to use and has an efficient One Button Operation. Our SPO2 Sensor will spot check and display in real time SpO2, PR, Pulse bar graph which great for checking your pulse signal strength RELIABLE AND ACCURATE: This spo2 pulse oximeter is not only durable but will have readings that are reliable and accurate. Comes with a battery-low indicator. 30+ hour run time. EASY AND EFFICIENT: 4-Way Rotating display and Auto-Power-Off after 8 seconds when finger is removed saves batteries. Over 30 hours of continuous use on 2 AAA batteries. PROACTIVE: Low battery indicator lets you know before your batteries stop working. NOTE: This device is generally used for Sports and Aviation , ts great for mountain climbers, bikers, trainers, aviators, and general sport enthusiasts to spot check SpO2 on the fly.Oxygenated blood absorbs light preferentially at 940nm (near infra-red light), whereas deoxygenated blood absorbs light preferentially at 660nm(red light). A pulse oximeter works by passing a beam of red and infra-red light through a pulsating capillary bed and then measures the amount of red and infra-red light emerging from the tissues via a sensor.The relative a bsorption of light by oxyhemoglobin (HbO) and deoxyhemoglobin is then processed according to the Beer-Lambert's law and the oxygen saturation level (SpO2) determined. For Sports or Aviation use.