I could go on and on about the benefits of giving your pet(s) access to the outdoors anytime they like, but I am keenly aware that is not possible in many situations.
There are a number of variations available with our enclosures that consist of wall panels and roofs which are both made of the same sturdy, power coated steel. The roof panels are designed to create a safe enclosure in 4’x4’ increments. This means the possible enclosure sizes could be 4’x4’, 4’x8’, 4’x12’, and so on. They are strong enough to hold most of the predators you will probably encounter (no real life testing has been done with mountain lions or bears).
I would like to offer you a word of advice if it is your desire to place the enclosure directly on grass or dirt. While all of the side panels have rubber feet to avoid direct metal contact with the ground, it opens up the possibility of either your pets digging their way out or letting the bad guys dig their way in.
At the very least, I suggest 12”x12” concrete pavers that are available at Home Depot, Lowe’s, etc. They offer a lot of defense against digging in or out. A 4’x4’ enclosure fits nicely into a 4x5 pattern of those pavers. For the 4’x8’ size, the pattern would be 4x9….and so on. I do not sell them but my experience has been they are somewhere between $1.00 to $1.20 each.