Scientific Anglers Sonar 10' Leader Kit - 6 DensitiesScientific Anglers Sonar Leader Kit helps you get a fly down into the strike zone when a floating line alone is not enough. Designed for freshwater fly fishing, these sinking leaders connect easily to the end of your fly line and help present nymphs, streamers, and spey flies at the depth fish are holding. Key Features Versatile Depth Control: Built to cover the surface to the depths, making it easier to match changing water conditions. Welded Loop