Sleep Number Mattres

The sleep number mattres isn't what you would normally think of as a mattres. It's really more of an air mattres with a pillow top on it. The inside of the mattres is literally an air mattres. It's surrounded by firm foam on every edge to keep it in place, and then it's inside fabric that looks like a mattres and has a pillow top on top (or just a little padding if not a pillow top). The foam around the edges is only a few inches, so the air mattres takes up most of the space inside the mattres.

For king and queen beds that have two air chamber, they just have two air mattreses inside separated by a thin piece of foam.