This cage is great for the price. The spacing is 0.4 inch, which is perfect for rats, and it assembles easily. The bottom slides in and out, but is only secured by two dangling metal pieces, and doesn’t fit as perfectly as I’d like. Nevertheless, it’s a huge upgrade and my rats spend more time running around in the top than they do investigating Weak points in the bottom! If you need a bigger, better cage for rats in a hurry, this one will do.