This mat is nominated for 3/8" carpet pile. I use it in a workplace organized in a bedroom with the usual soft wall to wall carpet. I measured the pile using a paper clip -- the technique suggested everywhere where the mats are sold. It was difficult to tell exactly because carpet hairs are uneven and bend easily. I eventually decided that they are 3/8" or less so I ordered this mat. Apparently my measurements were off. I got the mat with the cleats shorter than necessary so it tends to drift slowly over the carpet to one side with the rate of about an inch per day. When you buy the mat to use on a home-style carpet (as opposed to a firm office style) choose cleats longer than it would be required per measurement. Otherwise the mat is good and works very well.
So far it's working out like the one we had to replace that one lasted a couple of years but being plastic plastic does have a shelf life and gets brittle and cracks so if I get the same time with this one I will be happy
Arrived when scheduled by free delivery. Definitely go for this sturdier mat if your carpet has any sort of pile. It will still dimple with concentrated pressure over a small area for example the leg of a non-rolling chair but works well for rolling office chairs.
We have a low shag carpet and this is too weak to hold its form. Dimples are starting to form and the chair is becoming difficult to move. This might be good on very low tight pile glue down carpet that you see in office buildings but don't use it for your home carpet.