Try her...!
There are a lot of thoughts some good a lot bad about Hamster balls both of our hams never had any problems with them.
Forrest our first little one, actually worked out how to open his firstly by twisting the lid from the inside then prising the halves open..!
No such prob with Pip.
I have found the Hamster Balls from Wilkinson's to be very good, they only have one opening and are made from a hard clear polycarbonate, they are also very well priced too.
Make sure you wash them out regularly too as Hammies will Pee and Poo in a hamster ball.
Even though your Hams cage only has a top opening that is no reason to start taming, I have always let them come to me and be tamed at their own pace, if you get nipped you are only being tasted..!
Have fun...
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RIP Forrest 05.03.2016
RIP Pippin 05.03.16-13.07.17 I won't forget you.. Ghost 14-07-17-13-05-19
"Some Angels don't have wings, they have little round furry bodies, four paws, a round nose, curious whiskers and unconditional love.."