I used these to adjust cable tension on my SRAM rival front derailleur. I immediately stripped the first one trying to adjust the barrel while the cable was under tension, which I take responsibility for. I stripped the second one trying to loosen the barrel adjuster under no tension (the cable was disconnected from the front derailleur at the time) after about 2 months of use.
Jagwire seems to have the market cornered on inline barrel adjusters, so I am going to try a different one of their products next. Hopefully I will have more luck with the non rubber coated adjusters.