This Spey Swivel has a loop at one end only, and was generally intended to be for shooting lines without factory loops, such as: Scientific Anglers Floating Monocore, Scientific Anglers Braided PE, Varivas Airs, or Frog Hair. Attachments vary with the type of shooting line involved. Fly line type shooting lines are normally loop spliced, braided shooting lines are blind sliced, and monofilaments are knotted. There is no extra charge, except for the cost of the Spey Swivel itself for attaching one of these Spey Swivels to your line. If you order a shooting line and swivel in the same order, the swivel will be attached to the line when they arrive to you.