Barrel swivels are classified as part of the terminal gear that an angler may use while fishing. Terminal refers to various sinkers, hooks, snaps and swivels used to rig the line so that a bait or lure can be presented to a fish. Swivels are typically made of metal and commonly found in silver or black. Barrel swivels feature two connecting eyes that are attached to each other by a rotating barrel or cylinder in the middle. Barrel swivels act as a connection point and help reduce line twist especially when using spinning gear.