The chair mat fits the area perfectly. But when sitting in one place for longer than 5 minutes it get a temporary indentation - like a rut - that is hard to roll out of.
I bought the low pile carpet mat and it kept moving so I bought this medium pile carpet mat and it is doing the same thing. The teeth are about the same length so I don't see the difference in the low pile and the medium pile except the price
The chair mat was a perfect fir for my work area. It is made of sturdy plastic material and is holding up very well with the weight of the chair and myself on it. I recomend.