Pulse oximetry is a non-invasive monitor that measures the oxygen saturation in the blood by shining light at specific wavelengths through tissue (most commonly the fingernail bed). Deoxygenated and oxygenated hemoglobin absorb light at different wavelengths (660 nm and 940 nm respectively), and the absorbed light is processed by a proprietary algorithm in the pulse oximeter to display a saturation value. It is a standard monitor for all anesthesia cases in most developed countries  and also used in emergency departments, hospital wards, and ambulances to assess blood oxygenation in patients with respiratory difficulties or monitor for respiratory depressant effects of pain medications. Since its widespread use in hospitals, the incidence of unrecognized desaturations has decreased significantly . In addition to hospital-grade pulse oximeters, newer and much smaller consumer-grade models are rapidly gaining popularity in the sports, private aviation, mountain climbing, and other recreational activity communities. Because of the size and low cost of these consumer grade models, many patients with chronic respiratory illnesses are purchasing these to titrate either their medications or oxygen flow at home. However, most of those consumer-grade devices have not been evaluated by the Food and Drug Administration to diagnose or treat diseases.