Mats were shipped flat which allowed for us to use them immediately. When lifting them to clean underneath after a few weeks of use the plastic emitted a horrible smell which lingered the rest of the day. Not sure what is up with that.
our previous mat had permanent holes in it that caused the chair to be immobile. The new mat is much harder and we anticipate that the same thing will not happen to the new mat.
I like the mat very much. It has worked out very well. The only issue is the label that was glued to the top surface was difficult to remove and left discoloration on the area where it was attached.