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.
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.