The shelves are just wire organizer shelves, like those closet organizers. I think these were made for the bathroom though, to go in the corners and put stuff on. Yet they work absolutely perfectly for the cage. I cut up a carpet remnant and hot-glued that on there to be sure it wouldn't get kicked off. The shelves seem sturdy enough with the ties. I pressed down on them a few times to be sure they were secure and they didn't budge. But if I hear a loud thunk in the middle of the night, I'll know what it is.