At the company I work for, we are constantly developing prototypes and special products for customers based on existing devices that we have filed for. In order for us to determine the approval pathway, the regulatory department uses a flowchart/decision tree provided by the FDA in order to determine which classification the device will fall under. This process is mostly reserved for new products. Products that are minor modifications of existing products typical do not require approval. This places increased pressure to achieve results without introducing too large a deviation from the existing, approved device.