When the mat arrived I was worried because it came without any packaging and appeared to be badly warped. But after a while in a warm room it totally flattened out again! Very pleased with how it works. No more scratched floor!
the wheels dig in and you have to push out of indents. if you have a thin carpet with thin matting under it this is not for you. i'm thinking of taking it back.
I have to reset this sliding mat several times a day. I bought the one that was supposed to be appropriate for the type of rug I have under my desk but it's not holding its position in any way that's useful. Very disappointed!