The changing tray is a nice addition to the top of the dresser. It attaches to the top with two simple brackets at the back of both units, but does not seem flimsy when attached. It is a tad bit less wide and long than the top of the 6-drawer dresser, so you need to take the time to center it on the unit, but this is no problem and allows for a different configuration if you would like. Our changing mat fits very snuggly in the unit, but is a bit shorter than the space provided. It wont shift easily though, so it is secure for the baby. I am very happy with this purchase.