Ultra GSP is the strongest fly tying threadon the planet. Boasting a steel like strength for its weight, this thread really lets you put the pressure on! Our gelspun polyethylene is supple, ties flat and is available in the largest selection of sizes and colors. Choose 50 denier GSP for tying small trout flies with a minimum of bulk. GSP 75 and 100 have all around versatility for fresh and saltwater flies. GSP 200 is the size to choose for big deerhair work or when you really need to crank down!

GSP 100 has approximately 8 pound breaking strength