The Duncan's Loop form a loop at the end of the line. Unlike many other loop knots the Duncan's loop can easily be adjusted to the desired size before it is pulled tight. It is often used by fly fishermen to attach a fly to the leader but can be used in other applications as well. This compact knot is easy to tie and will retain around 85 percent of the lines original breaking strength. Watch this video fishing tutorial and learn how to tie a Duncan's loop knot.