The carpet and pad in our house is too thick for the 145 mm chair mat so I replaced it with the 170. The 170 is extremely stiff so that it is shipped flat and without being boxed however it arrived without damage. It still dimples slightly with my 210 pounds but is a great improvement over the 145 mm mat. I was impressed by the one-day delivery.
I purchased the version that was advertised as suitable for plush carpet. When in use the mat has developed dimples where the casters rest which makes it difficult to roll the chair easily. It should probably been thicker.
Don't be distracted by the cheapest price. Know the depth of your carpet; if you get this one and your carpet is too thick you'll just end up sinking and defeating the purpose of the mat. Be sure to get the correct one for your carpet.