The FDA divides medical devices into three categories based on their perceived potential to do harm. Class I medical devices are designated as low risk. These are products that don’t seem all that dangerous and generally are well established, such as enema kits, elastic bandages and manual stethoscopes. At 47 percent, nearly half of all medical devices are considered Class I.As such, Class I medical devices are subject to the least restrictive regulatory requirements. Most, for example, do not require a Premarket Notification 510(k) — that is, a manufacturer does not need to prove that its device is “substantially equivalent” to one already on the market.When it comes to Class II medical devices, a Premarket Notification 510(k) is one of the requirements. That’s because these devices are potentially more harmful than Class I products and therefore need to demonstrate safety. This division includes items like handheld surgical instruments and infusion pumps. These types of medical devices make up 43 percent of the market.Class III medical devices only make up 10 percent of all medical devices, and are deemed to have the highest risk. Generally speaking, a lot more than a Premarket Notification 510(k) is needed to get these devices to market.Replacement heart valves, denture adhesives, aspirators and breast implants — these products, and others like them, all require premarket approval before receiving clearance. That means more comprehensive and thorough clinical trials are required for these devices.