Did not come with lip but item numbers did match so description is wrong. Was also supposed to able to use on 1/4" deep carpet so item was misrepresented. Casters on desk chair makes dents in the plastic so rolling it is difficult.
The carpet protector has nubs that keep it in place in the rug however the mat is too flexible/soft. The rollers on my chair push down from the top and make indentations in the mat that stop the chair from rolling.
I'm really happy with the sturdiness of this mat. I've gotten some mats that mention sturdy but when I got it home, it was not what I expected. But this one is nice a sturdy.
The carpet chair mat is just what I needed to replace my former mat. It is strong enough to not have the chair sink into it, but continue to allow me to roll around on the mat. It is also big enough that I don't fall of the edge.