I've been using a Belkin Waverest wrist rest that eventually wore out after several years, so looked around for a replacement.
This Fellowes rest seemed to get good reviews, but as soon as I opened it I was struck by the fact that the whole thing felt very sticky, and there was a truly awful smell (a strong smell of an old stale dishcloth that made my eyes and nose sting after a while).
So I didn't use it, and put it away in a cupboard.
After a month or so I have just taken it out again, and it still stinks. However, the stickiness seems to have gone.
In personal terms it is too low, too hard and too narrow, so it doesn't properly support the wrist. Also, although the stickiness has gone from the surface, there is far too much friction so that it's not possible to slide the wrist along the rest. And, while it is "non-slip" on the desk surface, it takes it too far and actually adheres to the desk. I often move my keyboard a little bit, depending on what I'm doing, and I have to "unstick" it every time.
So it's going back in the cupboard and I've just bought another Belkin Waverest (unfortunately these seem to be discontinued as there is only one left anywhere on Amazon UK)