Purchased this because my 11 yr old Mini Schnauzer tore her ACL and my vet told me to keep her "low-key" for 8 weeks - no running, stairs or jumping.  I wanted something that wouldn't take up much space in the car when traveling, while also being bigger than a regular kennel box for her comfort.  This Pen is engineering genius! It folds down to the size of an artist portfolio case, yet pops open in 30 seconds without any effort and it is easy to move around from room-to-room and even outdoors. It comes with a nylon bottom that velcro's in place & a zip on nylon mesh top which is nice when there have been times of anxiety when traveling; she starts jumping on the sides ~ put the top on and she instantly calmed down. I wish I would have had one of these cribs for the past 11 years of her life ~ just a great way to contain her, without making her feel closed off from us!