UNI-Thread is one of the most trusted and widely used fly tying threads in the world, valued for its strength, smoothness, and consistency. Made from continuous twisted polyester filaments, it lays flat and doesn't fray like many flat threads. It is lightly waxed and comes on 200yd spools. 6/0 is a good all purpose size. Size Guidance: 8/0: Best for small dry flies, midges, and delicate patterns where a fine thread is required. 6/0: The workhorse size—ideal for most nymphs, streamers, medium-to-large dry flies, and general trout flies. Strong enough to secure bulky materials like deer hair, hackle, and dubbing loops while still thin enough for clean heads. 3/0: Heavier, stronger thread designed for large streamers, saltwater patterns, and bass or pike flies. Provides the strength needed to bind down big, buoyant, or slippery materials such as bucktail without risk of breaking.
