A double taper fly line may not be the most versatile of the bunch, but it's very good at what it's designed to do: delicate work at shorter distances.
Scientific Anglers // Mastery Euro Tactical Nymph Braided Core — Red's Fly Shop
Scientific Anglers Amplitude Textured Big Water Taper Floating Fly
Scientific Anglers Bass Bug Taper, WF6F, Frog Green/Shad Blue : Sports & Outdoors
Epic Glassline Double Taper Fly Line
Scientific Anglers Amplitude Double Taper Fly Line
Scientific Anglers Frequency Trout Double Taper Fly Line
Scientific Anglers Amplitude Textured Double Taper Fly Line
Scientific Anglers Mastery Series Double-Taper Fly Line Dark
Scientific Anglers Mastery Double Taper Fly Line - Dark Willow - 3
333 Double Taper - Freshwater Floating Fly Line - Cortland Line – Cortland Line Company
Scientific Anglers® Mastery Double Taper, Scientific Anglers Fly Lines
Video - Scientific Anglers Floating Fly Lines For Trout