I have a Martin's 685 (which I love) for my two adult girls but the only potential problem I see with it is that Martin's site noted that most larger Wodent Wheels would not fit into this particular cage. Does anyone know anything about this? I was sort of reluctant to get a wheel because I've heard that some rats don't like wheels but my girls seem so active that it might be a good idea.
What are your thoughts on wheels for girls and if they're a good idea, what can I use in my 685? Thanks!!!

I have the 685 cage I use for quarantine and I put the wheel in through the bottom of the cage and it fits nicely against the left side of the cage, it just won't fit through the front door.