Well, I'll try to tell you the best I can what size the small ones are. They are a little bigger than a fully grown hamster. (not a dwarf hamster, but a regular hamster)

They have large rats there too, and it's the kind we're wanting, but we wanted to get it from a baby and raise it our selves, because a lot of the full grown ones are scared to let you hold them and they run from you when you reach inside to pet them.