The FDA defines medical devices as: medical devices refer to instruments, equipment, appliances, machines, appliances, implants, in vitro reagents and other similar or related items, including parts or accessories, that meet the following conditions. It affects the structure and function of human body or other animals, and does not achieve its intended use through chemical reactions in human body or animals, nor does it rely on metabolic changes to achieve any of its intended uses.

The FDA clearly stipulates the product classification and management requirements of each medical device. At present, there are more than 1700 kinds of * * in the FDA medical device product catalogue. For specific classification, please refer to the detailed description of the product. According to different risk levels, FDA classifies medical devices into three categories (I, II and III). The first category is "general management" products, which refer to products with little or no risk, accounting for about 25% of all medical devices. Class II is a "standardized management" product, which refers to products with certain risks, accounting for about 55% of all medical devices. Class III products are dangerous or harmful, or used to support life support, accounting for about 20% of all medical devices. Implement the "pre-listing approval" (PMA) system.