Well, I forget, it might have been posted on Arizona Shooting -- however, I saw something along those lines, but it was made locally, and I dunno. I had one of those bandana things which I believe have the same material inside, and it was OK. It loses it's charge fast, but this looks kind of like, a higher level of that. However, that was only about fourteen or fifteen dollars, so, maybe these are ten to eleven times better than that. I would hope so.
You should buy one and let us know how that works for you.