The Stipula Superleggera cartridge fountain pen is a pocket-sized pen that reaches its full size when the cap is attached to the barrel. You can choose between a completely black version or a transparent version that changes color depending on the ink level.
 The elegant aluminum case contains two replacement cartridges.
 There's also a direct-fill version of the same pen, but it's currently unavailable. For this reason, the internal compartment also includes space for a dropper.