Danville 6/0 70 denier waxed nylon is the standard by which all others are judged. Over the decades I have occasionally had spools which seemed weaker or stronger than others, but overall this is the thread I have used the most in nearly 50 years of fly tying . Lays flat, behaves well, is not abrasive at all like many twisted threads, if you twist it with your bobbin it does what you want, if you untwist it during a tie it does what you want, it can be split easily for dubbing split-thread uses, it is well strong enough for dubbing loops on medium sized flies, it takes normal dubbing techniques easily, it is strong enough to tie in elk hair caddis wings and muddler heads.... on and on and on this is my all-the-time, every day thread for uncountable tying applications.
