RIO Powerflex Tapered Trout Leader 3 PackEach RIO Powerflex trout leader is designed for superb abrasion-resistance as well as high knot and tensile strength. The long, thick butt design provides smooth turnover while the supple tippet gives the fly life-like presentation. The light gray color is the most neutral and integrates visually with any background for perfect camouflage. All Trout leaders have a perfection loop on the butt.What is a tapered leader? A tapered leader is an extension of the fly line that is the same diameter as the fly line at the base where it joins with the fly line. From the base on down to the tip the line tapers down to a smaller diameter, thus the name.