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.
I bought this for my husband's office chair as he had worn a path down on the carpet pile and I had to shampoo it a lot! This mat works great for our office on 1/4" pile carpet easily with no slippage.
the pad thickness is thiner than my previous pad and hence allows the coaster wheels to sink into the surface making it difficult to move the chair. was not obvious when I purchased it . It appeared to be the same thickness and hardness. The store did not have options as shown online for better pads.