Pulse Oximeter measure blood oxygen saturation

A pulse oximeter is a small, non-invasive device that clips onto a fingertip to measure blood oxygen saturation(????????????2) and pulse rate. It works by using light to determine the percentage of oxygen in red blood cells and the number of times the heart beats per minute. This information helps monitor respiratory and cardiac function, especially for people with lung diseases, and is useful for home use or in clinical settings. 

A pulse oximeter (often called a pulse ox or fingertip oximeter) is a small, portable, non-invasive medical device that quickly measures your blood oxygen saturation level (SpO₂) and heart rate (pulse). It's commonly used at home, in hospitals, or by people monitoring conditions like COVID-19, asthma, COPD, sleep apnea, or during high-altitude activities.