Most of the router's hardware components are field-replaceable units (FRUs), which means that you can remove and replace them yourself. When you need to replace a router component, contact your customer support or sales representative to order the field-replaceable unit (FRU) that contains the component. For instructions, see Contacting Customer Support and Returning Hardware. For a list of the FRUs on the M20 router, see Field-Replaceable Units (FRUs).