I'm not sure if it's this specific model where they for some reason decided to include a little plastic advertisement on the soul of the slipper or if this is long running but the area right under the heel where the clear plastic rectangle is mounted. Was extremely badly designed. After about 2 weeks of light indoor use, both shoes are showing signs of the plastic working itself completely out on one one quarter of the corners. Don't expect these to last long but they are very comfortable while they last. Do not expect them to be at all puddle friendly due to the inevitable hole in the sole.