Ultra GSP is the strongest thread on the planet. Boasting steel-like strength for its weight, this thread really lets you put the pressure on! Our gel spun polyethylete is supple, ties flat and is available in the largest selection of sizes and colours. GSP 200 is the best size for big deer hair work or when you really need to crank down. 50 yard spools. The colours in this 4 spool combo pack are Black, White, Olive and Red.