The Uni knot or (universal knot) is one of the most used and versatile knots we use in fly fishing. Quick and easy to tie and is reliable with both fluorocarbons and copolymers. Useful tip... Once pulled tight the uni knot can be teased back to be fished on a loop. Great if you want your hook to sit further back from your tube if fishing with a long winged fly. If fishing a team of flies (buzzers) for trout, fish each fly on a loop. If you start getting takes but don't know which fly or what depth they are taking, look to see which knot has pulled tight. You now know what pattern or depth is working straight away.
We use the knot for: Tying Backing on to Spool. Attaching flies to leaders. Double Uni Knot - for attaching two leaders of different diameters