I love hand-knotted rugs, but one rug in a high-traffic area was getting a bit more use than the rest of the rug.  To keep it from wearing unevenly, I covered it with this clear protective mat.  The mat "grabs" the rug with little nubs on the under-side, but does not do any damage to the hand-knotting.  A good  inexpensive measure to protect the investment of nice rugs!