Button on top surface was loose on this. And as I use it as a foot rest when standing at my desk, I took the button off entirely as it was just annoying. Thankfully the other four are solid, as I think it would make the whole thing lose its shape if they were to come off. It's the perfect height for using as a foot rest (relieving pressure on lower back). I also use it next to my desk to rest papers etc on when I am working sitting down. Very useful. Too short to use as a seat except for a small child.