we had th eole fashioned wooden 4 sided one, used it heaps when we were at our holiday home where our dog comes inside, we would put jack int he pen with his toys then Harry (dog) couldn't slobber on his stuff, we also used one at home was perfect pop jack in it if I hung out washing etc, he was safe and again away from Harry also if I wanted to hang washing out and it was too hot out would pop jack in it with toys I then knew he was safe and sound.......we now use our as a barriers, one for our room doorway and one for spare room we have other 2 sides cable tied together for kitchen entrance