We purchased 4 sets of these to setup an outdoor play pen for our 1 1/2 year old triplets. Makes for a reasonably sized play area, and so far they haven't though to really try to scale them. Not really many places they could grab a foot hold which is nice. I love the flexibility of how they attach, makes it easy to arrange the space however you want. Very lightweight too, which makes for easy moving when we have the lawn mowed. Can just drag it out of the way.
Nice to keep baby out of trouble at home. Once he became mobile we had to do an "upgrade" as we noticed he was starting to hit his head on the X shaped metal bars. We tried some alternatives but the best so far was wrapping the metal bars with pool noodles (see picture). You'll need 8 pool noodles and some cuts (buy some extra in case you mess up). Use 2/3 of a pool noodle to wrap the internal bars and the remaining 1/3 to wrap half of the external bar. The pieces will also need a longitudinal cut along the length to fit the bar in. You'll also need some small cuts in the middle of the longer piece to fit the center rivet, where the mesh is attached to the bars. We got the pool noodles at the dollar store nearby for less than $10 and since ... full review