This is my go-to flat nylon tying thread. The wood duck color is a secret weapon for BWO nymphs here on the west coast. Like most nylon thread, it does have a tendency to fray a bit.

Ultra Thread is nice because it flattens easily. The 70 denier is strong and the heavier weights are nearly unbreakable. My only complaint is the color consistency from lot to lot. I ordered a replacement spool for Brown and it is much darker than the spool I had. It’s nearly as dark as my spool of Dark Brown.