Rediscovering the art of writing
What is the difference between a ball pen and a rollerball?
   

A ball pen or biro uses an oil-based ink whereas a rollerball uses a more fluid ink that gives the impression of writing with a fountain pen. The advantage of a ball pen is that the refill is longer lasting. Rollerball pens normally have a cap to prevent the refill from drying out though there are some capless rollerballs such as the Lamy Swift and Cross Edge. Some rollerballs can be converted into a ball pen, such as those in the Cross range.