This mat protects the carpet and makes it easier to roll when seated. After sitting for a while it dimples under the castors and would be better if it were stiffer. That being said it is significantly better than nothing but carpet.
Picked this up at the local store they had plenty rolled up ready to go. It will dent up some if I sit too long in one place (I'm a heavyweight) but next morning it's smoothed out. Chair rolls nicely on it ove the carpet.
It is good for being over carpet but when I sit in my chair it sinks into the plastic leaving prints. I only am 190 lbs. a male. So. It’s not smooth. Those marks stay there. It’s like to memory foam like. Lol