Stops the paper towels from running out too fast.  I was looking for something for under the medicine cabinets in the bathrooms and local stores only had cheap and unattractive plastic ones.  This was just what I wanted.

Pros: Looks good and works well.
Cons: Makes a clicking noise when the towels are being pulled off that some folks may not like.  It doesn't bother me, but I mention it in case it's for a bath located near a bedroom; it might disturb a light sleeper when used.