The pulse oximeter is a noninvasive and small device used to monitor the level of oxygen in the body and pulse rates. It is a banal test that measures your amount of oxygen carried in the body. This device attaches to your fingertip dispatching two wavelengths of light to measure your heart rate and how much O2 in your blood. The oximeter completes its test its screen will show the percentage of O2 in your blood coming from your heart. It’s commonly applied in critical situations like emergency rooms or hospitals, doctors may use it in home offices.