Our 2 kitten saves LOVE this!  They do use the center to sharpen claws & those balls jingle A LOT.  There was no assembly required.  Will try to get pics.  These kittens are siblings, they are sequestered in our guest bathroom to learn using the litter box & become social. The vet estimates that they are 2 months old.   The guest bathroom, now "the nursery"  is right next to my office.  They really go after this awesome box.  Thanks, WAYFAIR!