Semperfli Nano Silk 18-0 (30 Denier)

It doesn't come cheap but this is the strongest and smallest tying thread on the market today. This thread is a minuscule 30 denier, but being a micro gel-spun thread it is exceptionally strong. There is nothing better for the small fly addict to whip up micro dries and nymphs with.

-50 m spool