Ronstan Parrel Bead or Trimmer Bracket Stopper Ball is the most convenient way to terminate control lines while also providing a simple, textured grip for pulling. The trimmer bracket stopper ball has a recess in one side to contain the stop knot and made from strong, durable and high quality plastic impact resistant, U.V. stabilized Nylon. The stopper ball is located at the connection point between the flag-out bungee line and the fly line right at the trimmer bracket. If you have had a line go or problem then this often vanishes in the ocean.