A pulse oximeter is a small, non-invasive device used to measure the oxygen saturation level in a person's blood. It typically clips onto a fingertip and uses light sensors to determine how much oxygen is being carried by red blood cells. This information is crucial for monitoring respiratory conditions and ensuring that the body is receiving enough oxygen. Pulse oximeters are commonly used in hospitals, clinics, and at home for patients with conditions like asthma, COPD, or during anesthesia. They provide quick and accurate readings, helping healthcare providers make informed decisions about treatment and care.