Absolutely love the Danville 210 Flat Waxed, but also have to say for some sizes I do like using 140 denier of the same kind. Also some colors like Purple for example don't come in flat waxed so get the FlyMaster Plus in 210 and you may like it even more? I even use some 6/0 Uni thread because they have a few colors I can't get in Danville or other MFG's.
Alao while expensive there is a thread named Veevus that is very strong for its size and I use a little of it in 6/0 for a light blue color. Now I see they have some heavier stuff that I have not tried, but this stuff is too costly for normal jig tying! They even have some 240 denier stuff, but cost almost $2 wholesale! Yikes!!

also have to say I have some of the WAPSI Ultra Thread and it's much like Danville in size and use, but where I use to buy it no longer carries it at all and only place I could get a price I was willing to pay. It is good thread as far as I know, but most likely will not buy any more.

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