I must admit that I bought one of these because I wasn't quite sure if I was hearing correctly; in particular, what the nice people in the Thomann VT demo were saying. The implication seemed to be that, all of a sudden, for whatever reason, we bass players had lost the ability to use open strings correctly. Instead of producing notes of a similar timbre and envelope when compared to their fretted relatives, apparently an open B, E, A, D or G (sorry, I don't do six strings) provided nothing less than an enormity of sustained resonance (or similar).
Clearly, this was not, in the least, tolerable and hence, we were all in need of muffles, or rather, fret wraps. Allegedly, they could be used further up the neck too, but again, I wasn't trusting my ears; so ordering one seemed appropriate.
A short time later it arrived. I unpacked it and looked at it. I looked at it again; and again; and, maybe some more. But, eventually, I went off to play a few of my basses; just to check that I had indeed lost the ability to muffle open string notes (and others), for whatever reason, after over 40 years of bass playing. I hadn't. Seriously; I double-checked: I hadn't. I could still play an open string in pretty much any fashion I wanted i.e., from a muted percussive effect (with no standard pitch correlation) to a full-blown resonating calamity; as you might find appropriate at the end of a Neil Young track e.g., Welfare Mothers. But, then again, I can do that with a fretted note too!
So, I went and looked at the fret wrap again, upon which I decided to place it, out of the way, above the nut, on my six-string bass; the instrument I will never own. But, at least the fret wrap would be safe until that time which will never arrive because, just like a six-string bass, I have no need of such an item and, I'm damned sure I never will; as I would imagine is true for many other bass players; at least in terms of fret wraps!
So. In summary. Fret wraps? Gimme a break; whatever next? A six-string bass, perhaps? Seriously? Okay then, as long as it comes with its own fret wraps, I guess that will be okay (not).
PS: And if you really must, make your own out of Velcro; at least it will save you some money and give you a wrap that fits your bass properly. Although why?; why? why? ...