"These are great, my mice love them. My mice live in a 10 gal glass tank, I connect these in whatever pattern seems fun and put them in the bottom of the cage. I even build up to give them more room/fun. A few things I really love about these is, they are clear so you can see your pet when they are in the tubes, they come apart so you can clean them when needed and they are changeable so you can put them together new ways to change things up for your little friend."