This pen was practically God-sent for my two 5 Month Jack Russel Terrier puppies. I live in a studio and although these pups get regular excersice with walks and visits to the local dog park, this pen provides a great way to give them their own space to play. It also prevents me from having to follow them around to see what they are getting into. The pen is attached to two pets crates. I own the small crates for each dog and they are stacked one on top of the other, which is the exact height of the pen. The pups can go in and out of their crates freely and into the pen. They love it and so do I.