These are the basic entry level offer for the segment- won't satisfy any gram needs, but more than get the job done. When I installed these on my vintage 27 wheel they stretched out into an oval shape at the valve stem and were a little difficult to set properly. Make sure when installing to not stretch the valve stem area to avoid any potential rips. As for the function, these work well to prevent punctures and I have had no flats to date. These are a good no frills strip for your rims. I would recommend buying rim tape if possible for more long term protection, but these also serve the function well- and this company supports their products well, so make sure to buy here for customer support.
I knew the wheels might need some cleaning up before I mounted the Conti retro 26ers on my daughter's latest bike - a Specialized Shark. So, I got these rim strips to protect the new tubes and they fit the interior width of the rims just right. I initially thought they were too wide, but the more I worked on centering them and considered what would happen in there with the tires mounted and the tubes inflated I realized these would be spot on.
Quick & easy, no issues with 'em so far. Tape's probably better on a couple levels, but for my purpose these were great. The old rubber strips on my 45 year old bar bike rebuild lasted 40 years (one was still good) so I'm not too concerned about longevity etc.
I bought the 27x1 18 and it fit my old 27 inch single wall rims perfectly. They stretch fit over the rim and fit snugly in place. Very satisfied. It beats trying to do a makeshift rim strip out of duct tape.