It arrived flat which was nice. Not as stiff as I had hoped and the bumps on the bottom that go into the carpet are not as long as I had hoped. I have a thicker carpet and I need to keep readjusting it because it slides---not much but enough where I need to keep shifting the mat. If I didn' t have such a thick carpet it probably would work fine.
Great for "temporary office" at dining room table. Not quite thick/hard enough for rolling office chair and my weight; wheels tend to sink in part way. Otherwise perfect for the current purpose.
This mat works pretty well. It allows my chair to move more smoothly over the carpet. However the plastic is soft enough that it will temporarily deform and create little "ruts" - and I'm not a big person (165 lbs.). These requiring a bit of a shove to slide out of.