Your cat is movin’ on up to a deluxe apartment in the sky with Catty Stacks Modular Cat Condos. Get your favorite kitty some strong, stackable, exploring fun with Catty Stacks Modular Cat Condos. Easy to build, stack, rearrange and clean, these super strong Corrugated Ultraboard boxes provides hours of fun for your cat. $14.99 – $59.99