Feeling short of breath? Find oxygen levels at home! A pulse oximeter is a non-invasive probe that measures oxygen saturation in the body to determine whether you are getting enough oxygen. In a hospital, the probe is usually clipped on the finger and it uses light to determine how much oxygen is present in the blood. Having a pulse oximeter at home can be useful for checking oxygen levels after strenuous activity, as well as to check if you need a ventilator or sleep apnea mask. Pulse oximeters may be an especially good idea if you have conditions such as heart disease, COPD, lung cancer, asthma or pneumonia among others. If you may be in need of a pulse oximeter, read on to discover the best options available and where to buy them.