Review on Heavy Duty Foldable Dog Pen - Portable & Versatile Indoor/Outdoor Barrier For Pets by Jason Winkfield

We have a tiny dog (maybe 8 pounds) who is quite energetic - he can jump over it. Pick the taller size. Also, this works best on FLAT GROUND. On our uneven yard, it is also possible for the same small dog to wiggle under it.That being said, it is very helpful and very mobile. If your dog is not a young unsocialized puppy, it is probably enough deterrent to stop wandering. It is a bit heavy, if you intend to move it around (I'm 5'2" and not very strong).