When the product came rolled up I was fairly sure there would be an issue. After 5 minutes on the chair mat I had to bump the chair out of the sunken castor ruts. Way too thin for carpet applications ie. CHEAP
The smooth nub design on the bottom is safer than the pointy nubs but they allow the mat to move around more on carpet requiring frequent repositioning.
I purchased this for my office with a med. pile carpet. I am 200 lbs and I don't have any problem with divets or anything in it. I plan to order an additional one.