Nothing too formal. A nice blouse/shirt and good pants to match it. The managers don't seem to focus too much on style. Make sure to be polite and smile!
Something presentable. Doesn't have to be fancy.
Dress to impress.
If attending an interview, a very nice shirt and pants should be the minimum attire to show that you mean business. A dress or a dress shirt can also be worn if you really want to dress to impress.