It's sized for small kittens only.  The three top platforms are 9-1/4 inches square, whereas my two cats are 20 inches long, plus tail.  No way they could turn and twist through the 2 box openings either. My cats like to be high, but they also need a sheltered feeling.  The top tiers would be better served with an enclosure, like a small laundry basket.  I am returning it.