ordered a "mat" thought they were all the same!! Well they are not! There are mats for different thicknesses of carpet mats for different hard surfaces. Bottom line now I have a "used"mat that does not work. In addition we have to get the proper mat! Hopefully I ordered the mat for the correct thickness of carpet(which I measured with my trusty paper clip) as shown in a diagram!! My advise is categorize the mats according to what kind of flooring they will be used on and of course dimensions and shape.
First it was difficult to unfold and place where it was needed. Second it is difficult to roll my chair (or any chair for that matter as I tried 3 different chairs) on it to get a comfortable seat in front of my desk. I hate this product!