I think Fix-O-Flex has become the generic term for all of these stretchy bracelets (much like Kleenex or Bandaid), there are some that are better than others. I have a bag of them I’ve pulled off of watches over the years and I have tried a few- they are very comfortable. As I tend to swell during the warm months going from air conditioning to summer swelter, my wrist can change size as much as a 1/4” from morning to afternoon- and a stretchy bracelet would be appealing- i get why they were popular. My grandfather always wore them on his casual watch and I remember the Speidel stands on the drugstore counters as a kid.
I think many collectors these days think they were always aftermarket drug-store garbage, but several companies offered these as a factory “upgrade” over leather, so worth doing the research when one comes attached to a vintage watch before chucking it in the bin.
