I just read about those in an ad. I have never before seen earbuds with swappable cores, depending on the setting and what kinds of sounds the wearer is trying to block. The ocean kind looks especially good. I wonder if it would be possible to get just that (ocean version) and not have to listen to people talking, tv, etc.. Has anyone on here used them or heard whether they're good, bad, indifferent? I guess about 40 bucks would be all right.