This exercise pen is sturdy and easy to put up; it also creates a good size space when put into a circle. I bought this pen to use inside and learned that it could quickly be manipulated by my 10 pound puppy at no fault to the crate. If there is nothing to tie down the pen (for example using it outside with stakes...which it does come with)  then of course the pen will move as the dog pushes it.  My only suggestion to buyers would be to really think about the height you need. I ordered the 24 in H thinking no way my puppy could climb it, FALSE, and she climbs it with ease. However not at dogs are the same.