Buy a Scientific Angler Ultra 4 Freshwater Fly Line online. For more information or to view another Fly Lines product, click next item. To return to where you were before, use the current page links below. Fly Lines and other boating equipment and supplies can be found at BoatingMarina for a discount! Scroll down for price, descriptions, reviews and more. Shop at BoatingMarina online and avoid the run-around often required for hard to find boating gear. Use our Product Search tool to locate specific marine parts and equipment. Thank You for shopping at BoatingMarina!