Hey there! The diameter of the 11.5"’ runabout ball is 11.5” the size IS the diameter on these.

While it certainly is large enough for two male rats, it really depends on the rats. Mine didn't like it at all and pooped every time I tried so I repurposed it into another hide space. Free roam in a "safe" area is much better.

Actually, we don't recommend our Run-About balls for ferrets due to the curvature of their spines. An alternative for your ferret could be our Flex-E-Fun-Nel!

Hi there! We recommend hand washing the Run-About Ball.

Its a clear hard plastic similar to the one used to make small animal carriers and hamster tunnels.

No animal should go in an "excersize" ball. Hamster62, if you are the "Hamster Whisperer", you should know that. Normally, the running that they are doing inside the ball is a fear reaction. Hamsters and mice like to sniff their surroundings, as they don't have very good eyesight but like to explore. Forcing them into a plastic bubble robs them of that. Plus, they cannot (or will have difficulty) hiding, which is something that they naturally need to do as prey animals. The best thing you can do for them is to get them a playpen or do supervised free roam time. My mice come when called, so I can let them out in an enclosed area and call them back when it's time to go back to their cage. You can voice-train your hamster by sitting in an enclosed room (bathrooms are preferred as they generally do not have a lot of clutter, but any tidy room will do). Bring treats. Call your hamster (most animals already at least somewhat know their names, so this isn't as hard as you think,) and produce the treat. Repeat until your hamster will come to you WITHOUT needing a reward (treat). Ta-da! Now you can let your hamster free roam whenever!

Actually the smallest you could get them is 8” 5 is way too small!! The bigger the ball or wheel, the more the hamster will feel like it’s running which means no back issues!

Yes,sizes are adjustable.