The devices typically have several different modes of operation. In mono-polar output, the current will flow from the surgical site to the unit by using a return electrode. With bipolar output, there is no return electrode used, and this is typically used for more precise and delicate procedures. However, it is important to note that not all of the electrosurgical units offer this option. The devices offer up a number of other modes and features that are helpful for different types of procedures. Many will also have, or come with the option of, a foot switch. This allows the surgeon to activate different modes on the device simply by pressing the switch with their foot.