World’s Fastest End Loop Knot! The perfection Loop is similar to the double dragon knot and the Bowline in some ways. It’s often used in fishing as it’s one of the easier loops to do with a very thin line (vs something like the bowline) Chief upside is Speed and adjustability, chief downside is it can’t be tied around an existing object - though you can tie it around a hook for example and thread the hook through the top loop.