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.
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.