Works great for Ferrets or larger small animals. Don't think you can buy a better cage. You can let the animals go between the two units or close off the opening and have two separate units. There is also an add-on unit (no stand and it mounts on top of these) available so you can go 3 high. I suppose you could go higher but it wouldn't be reachable. If you have smaller small animals like sugar gliders you need to go with this cage. It is very similar but has smaller wire spacing.