When fly fishing being able to turn the flies over is essential for a good cast. This tis the part that a tapered leader plays. Tied directly to the end of the fly line tippet is then tied onto the tapered leader, As the name implies it is tapered and the rating given is that of the thin end, the end closest to the flies. Available in different lengths and weights. In New Zealand where some times the water can be very clear and the fish spooky a longer tapered leader is more ideal.