Bought this for my pack (4) kittens...they love it!  I hung it on our sliding glass door, works great because it folds up & stays when I need to close the blinds.  My kitties are now over 10 lbs. now & 2 get up there & it still stays attached, no problem.  Could hold more, but there isn't enough room for 3+.  Well worth the wait & price.