the only thing I would change on this is to zip out the bottom (like the top is).  Any inquisitive cat (and what cat isn't) will eventually try to lift up the bottom (where velcro strips hold to sides).  We alleviated some of the 'distraction' by putting a rug/blanket in there when were using it. Other than that it is a wonderful product and our Katie is enjoying  the outside without us having to worry about her scooting off somewhere or chasing down a bird.