I had seen those at the Eukanuba Championships, I think...one of the vendors there. I would LOVE to see if they really work. I have one here who chews the edges on just about anything other than the fake sheepskin ones with the rubber backing. They do give a guarantee, but it looks like they only replace, no refunds.
These are the only pads Piper is allowed to have in her crate I'm not sure if they're just not interesting enough to chew, or if she chews them without leaving a mark, but they look good as new at over a year.
I have two. Kodi chewed the edge on one of them and a bit of the pad, but not the other. After the initial chew, she has left them alone, but I do cover them with a blanket now also. I probably would buy more of them as they fit pretty well in my ex-pens and are easily washed. Hopefully Kodi is past her destructive period (knocking on wood as I type this).