Do you mean these?
https://www.brownells.com/gunsmith-.../elastomer-pad-for-multi-vise--prod22186.aspx
If so, I've had a couple of sets for over 20.... maybe 30 years and get a fair bit of use out of them.
I liked the first set enough that after I modified the bottom slot for one vise, I bought another set for a different vise. They used to be considerably less expensive and were great to buy and customize for particular, repeated jobs.
I have probably 20 or more sets of various vise jaw pads and covers and they are among the most often used.
Have held up superbly though, as with leather, you must always check that they have nothing imbedded in them each time you use them.
Too, as they are considerably larger in surface than most actual vise jaws, take care that the work is properly seated 'twixt the jaws and not centered above or below.
Todd.