They are made for small to medium breed pups weighing up to 40lbs.
They do not tip over because of the weight of the pen and the rigid frame, however, the acrylic wall panels may break under excessive force. Therefore, we have a recommended weight limit of 40lbs. If your pup is very stressed or aggressively trying to break out of the pen, we do not recommend using the product regardless of the pups size or weight.
The video below demonstrates the rigidity of the assembled pen.