Sonik Short Head Spey Lines Fly Fishing lines. Sonik Short Head Spey fly lines - the unique profile of the Sonik short head spey lines are designed to perfectly match Sonik double handed rods, and makes them incredibly easy to cast. With head weights that effortlessly load our rods, the dual colour for clear identification of the end of the rear taper shows the ideal point at which to lift off and recast. They are a joy to use and will help you place your fly in those ‘hard to reach’ lies on the far bank, time aftertime.