I am using these indoors and they work exactly as I wanted.  I have an long hardwood stairway with two twists that is a focal point in my foyer.  I didn't want to cover it with a runner, but as I am having hip issues I wanted to be safe. These have a nice deep color and the pattern makes them look richer.  Ordered one box for trial and ended up ordering 3 more (4 treads per box).  Not the cheapest available but definitely the best looking & their rubber backing holds them in place.