I have one robo hamster, id reccomend a 70x40cm cage for one
they are very active
You need a lot of patience with a robo, it has took over 1 year for Pip to trust me, and he still isn't 100%
they are adorable though
Here is my setup for Pip, he is in an Imac Bingo
1cm Bar spacing is not suitable
Were are you from, as that will help with cage suggestions?