Why did I wait so long to try this stuff? I bought a couple spools in colors I use the most to try and I was not disappointed. It's very thin, but it's meant to be. It's super tough and I've yet to break it when tying the same flies I've tied with other brands of threads. It does not bulk up or build up and that can hurt if your trying to add taper to your fly body, but it can help you too. By not building any bulk, it is very easy to build and finish the head of my flies without overcrowding my hook eye. My only negative thing to say is that it's pricey and you only get 50 meters on a spool compared to other brands/types of tying thread, but this stuff ties so well and has so much going for it that it's worth the price.