Semperfli Nano Silk 50D Fly Tying Thread

Discover the go-to GSP tying thread trusted by professional fly tyers worldwide. Engineered for exceptional strength and precision, this ultra-fine 50 denier, 12/0 thread delivers unrivaled performance from micro patterns to larger flies, making it a versatile essential at the vise.

Built to be super strong yet incredibly thin, it is up to 10 times stronger than steel of the same diameter and stronger than many heavier polyester options—so you can pull tight without fear of snapping. Its fine profile is perfect for delicate work on small hooks, yet it retains the power needed for secure wraps, durable heads, and confident finishing.

Designed to lay perfectly flat, this thread virtually eliminates build-up, even after dozens of wraps, helping you maintain slim, refined profiles and neat heads. It also splits easily for dubbing, allowing fast, clean dubbing loops and precise material control for a professional finish.

Ideal for a broad range of fly sizes commonly used by most tyers, it excels on patterns where you don’t want the thread to show. Whether you’re tying nymphs, dries, emergers, or streamers, you’ll appreciate the reliability, smooth handling, and consistency that make this premier GSP thread a favorite at every bench.

• 12/0, 50 denier GSP thread
• Breaking strain: approx. 1,900 g / 4.2 lb
• Lays perfectly flat to prevent thread build-up
• Exceptional strength-to-diameter ratio
• Can be split for easy dubbing

Tie tighter, cleaner, and more confidently with a thread that keeps up with your most demanding techniques.