The foam lining I am guessing is to be used inside the ear cups, but since they dont come with any instructions I couldnt figure out how to use them. OH! They were much cheaper than almost every other unit I looked at. Im happy with my choice. Its really cute and seems to be sturdy enough. Decided to go for something this summer with a little more style than the basic flip flop and have loved them. I am using for kitchen items I use everyday. Everything was inside and undamaged. Not as comfortable without socks though. I really like this shirt.