I have two cats that are both a bit on the heavier side, they have no issue going to the top and our younger cat rascal loves to sleep up there and get sunlook out the window. It has a strap that you can screw to the wall and if done right it really stabilizes it. It’s compact but does trick, was easy to assemble but be sure to put the supports in the little open spaces on levels 2 and 3 first and go from there