They did not have non slip backing on them and when I put them down, I slipped and fell and I am 79 so I was not too happy.  Now I will have to buy the sticky stuff to put on the back, which makes me unhappier.  Thank god I did not get hurt bad.  Just a little bruised.  Would send them back but way to much trouble.  Every I order something that I can;t return to store, I alway regret it.