Rio Premier Technical Euro Nymph LineRIO TECHNICAL EURO NYMPH LINE Built on a monofilament core that creates a stiff, slick line for quick feeding and less line sag between the rod guides, and an ultra thin diameter to maximize sensitivity, and for lightning fast hook sets. The core extends past the front end of the line to become a leaderresulting in no knots to get caught in the guides. The leader is . 013" in diameter, pink to be easily seen, and is level, so can also be cut and tuned