Came rolled up so I could not use it for a couple of days. After that it worked fine however. I would recommend not using this on a hard wood floor though as it would scratch it. It is great for my carpeted floors though.
I use this mat over a vinyl floor. It needs to be much thicker to provide a smooth rolling surface. I have a chair with 5 casters on it and they create divots on the mat. I weigh 200 pounds; so that distibuted over 5 casters should not create divots in a supposedly solid pad.