The first one that was delivered came extremely warped so I returned it to the store. In the store they suggested leaving the mat in the Georgia sun on a concrete surface in order to flatten it out. Next time I ordered one it worked!
Bought this mat to replace one I had had for years. Didn't realize that it was smaller and thinner than my previous one. I think it will work out fine as I am not in the office many hours a week and don't weigh allot. It looks good and so far is working fine. Worth the money.