What it is
Hareline Uni Yarn is a fly tying yarn made from a 2-strand acrylic material on a spool. It has a slightly buggy look but still lays down in very consistent wraps, and it feeds cleanly through a bobbin so you can wrap it like thread. If you need more bulk, you just add wraps to build thickness.
What to tie with it
Use it for smooth, controlled bodies on nymphs, emergers, wet flies, streamers, and even salmon and steelhead patterns where you want an even profile without fighting loose dubbing. You can wrap it directly off the spool with your bobbin, or vary the taper by changing wrap count along the shank. It also works as a simple tailing material when you want a short, buggy-looking tail without adding more steps.
Flies and the fish they're for
Uni Yarn shows up as the body material on a lot of everyday nymph and wet-fly style patterns that get fished for trout in rivers and tailwaters, and it crosses over well into streamer bodies for trout and smallmouth in moving water. In salmon and steelhead flies, yarn bodies are a common, durable way to build a clean silhouette for anadromous fish in larger rivers. It’s a practical choice any time you want a wrapped body that stays consistent from fly to fly, whether you’re tying for freshwater trout or stepping up to steelhead and salmon.
How it compares
Compared to dubbing a body, Uni Yarn gives you more control over how buggy or smooth the finished body looks, because you’re wrapping a uniform material instead of managing loose fibers. The tradeoff is you usually have to work a little more to get the same “alive” texture that dubbing can give right away.
