Medical devices classifications are broken down into class I, class II, and class III devices. How a device is classified depends on how much of a risk the device presents to the user and how novel the device is. It is up to the FDA to determine which class to classify a given device. Class I devices are the lowest risk devices and are therefore the ones with the least strict regulations. Class II devices are more high risk, but many times they are substantially equivalent to a predicate device and then it is up to the company to demonstrate substantial equivalence on a 510(k). The third class is the Class III device which is the most high risk and often either supports or sustains human life or is a completely novel device for which there is nothing substantially equivalent to compare the product to. Class III devices therefore are the ones out strictly regulated by the FDA.