Is it a rollerball pen? Is it a fountain pen?
The answer to both of those questions is, in a way, yes.
The Recife Riviera Traveler Hybrid Pen takes elements from rollerball and fountain pens and combines them into one. With a rollerball tip, it looks like an ordinary pen. However, opening the pen up reveals fountain pen cartridges! Taking a standard international cartridge, this pen allows you the freedom and selection of fountain pen ink colors, but the smoothness and writing function of a rollerball. It's the best of both worlds!