We are very disappointed with the Farrel Moroccan Stair Tread purchase.  The treads wound not stay in place with its non-slip backing so we used two sided tape.  When we tried to lift one tread, the carpet came apart.  One part of the tread stayed with the tape on the stairs and the other tread came up.  Part of the carpet pulled through the backing, so now we have holes in the carpet treads. We are replacing treads that have been there for 20 years and we pulled them up with no problem. Hard to believe old treads are better than new ones.