Also known as Fustats & trade; or Nontamperable. Similar in design and use to a plug fuse. However, it prevents anyone from replacing a lower-rated fuse with a higher one. Has two parts: the fuse and the adapter. The adapter has a different diameter for each fuse ampere rating. Once the adapter of a particular size fuse has been inserted into the fuse socket, it cannot be removed. Only fuses with the same rating can be used in that socket.