Don't ever forget how to tie that knot again! This 3 card set fits easily in a shirt pocket or tackle box and also folds out to a 12" ruler. Waterproof plastic cards feature clear illustrations of 10 most popular knots: Improved Clinch, Palomar Knot, Uni Knot, Surgeon's Knot, Double Uni Knot, Perfection Loop, Dropper Loop, Surgeon's End Loop. Nail Knot and Blood Knot. 4x2 inches. Stashed smartly in your glove box, with a quick peek at these little plastic cards, you are confidently cinching down that prized possession with a series of Bowlines and Trucker's Hitches like a pro! That is the idea behind the knot cards - having them handy when you need them.