They do not...the line is wiry. The highest rated ester line I have seen was 4# test. I tried it and it was just too hard to manage. I have been fishing ester lines for a number of years now and I love the stuff. I tried a lot of brands before settling on the ester lines from Varivas. I used their Area Super Trout Master Limited Supr Ester in Neo Orange for years then started using the ES 2 Lemoni Ester a couple of years back and that is the only ester line I now use. I have several videos on my YouTube channel discussing ester lines...TroutMagnetMan.
Regards