Outstanding structuring and easy to assemble. Added curve pieces and able to set up on small apt balcony such that my cats can go in and out with a partially closed balcony door and only the opening of the kittywalk available to them.  They love it and spend 50% or more of the day in it while I’m at home free to do things without worry of them jumping on the rail or catching a bird. We couldn’t be happier!