In the Wave High Z-Drag Rescue Crib Sheet, all the essential knots and boat retrieval techniques are clearly illustrated and explained on durable waterproof paper that folds out. A great tool for clubs and schools as well as individual boaters. Information Included: Basic Z-drag 3:1, Vector Pull 2:1, Z+C 6:1, Double Z 9:1, Water Knot, Double Fishermens Knot, Prusik Knot,Double Figure 8 Knot and the Bowline Knot.