In-line fuse holders are wire-mounted holders that connect anywhere along a circuit to protect specific lines. They allow these lines to be isolated in the event of a fault so that the rest of the wiring system won't be affected. They have a receptacle that encloses a fuse and pigtail wires or terminals that extend from each end of the receptacle for connecting to a circuit. These fuse holders are commonly used on automotive wiring and other applications where space is limited or fuse box would be impractical.