The mat locks perfectly into our extremely low-pile non-padded berber carpeting. I've used it for 2 weeks now and no deep indentation from the chair. If I do get a slight indentation it's gone the next morning.
Chair gets caught on the lip of the mat and even tho we considered the bamboo because of the hardness in a couple of weeks time it has already sustained chair wheel marks. I do love the color tho. The dark brown blends in well with our dark brown carpeting.