SF 2 in 1 Fly Fishing Angler Accessories Knot Tying Tool Knot Tyer The Knot Tyer is praised by fishing experts for its simplicity and for the strength of its knots. It can be used to tie a number of different varieties of the nail knot. Unlike other knots that have only one turn holding their ends, the nail knot cannot become untied because the tag end of the line is secured by all turns of the knot. The NAIL KNOT is the most affective way to tie any size monofilament to your line. It is a smooth and secure knot that easily passes in and out of the rod guides. With this knot, the harder you pull the better it "GRIPS" and holds. One year warranty,free replacement