this pad was purchased for an outdoor patio made of aggregate concrete squares which are very rough on bare feet.  This pad provides a cushion for the rug I purchased to go over the patio plus keeps the rug in place.  It is also made of a material that is waterproof or rain proof or sprinkler proof so my rug made it through the whole summer without a cover over it.  Leaves fell on it, but it did not get damaged by the stones or any standing water beneath it.   

Pros: good cushion and waterproof
Cons: cumbersome to spread out and store.