RIO Premier Technical Euro Nymph LineTechnical Euro Nymphing Line with integrated leader. RIO's Technical Euro Nymph line has all the assets for the modern nymph angler. 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 lighting fast hook sets. In addition, the core extends past the front end of the line to become a leader resulting in no knots to get caught