With more than 45 ounces of felt and rubber per square yard, Carpet Lock provides a concentrated, dense buffer between your carpet and rug that prevents shifting, wrinkling, and bunching under foot traffic. Carpet Lock felt under-surface is uniquely textured to fasten itself to the fibers in your wall-to-wall carpet; its non-slip natural rubber surface layer is designed to prevent rugs from buckling & sliding while walking on.