This amazing pressurized ballpoint refill from Fisher fits in any Parker-style ballpoint pen. It comes with a special adapter that makes it a perfect replacement for your Parker-style ballpoint refill. If you have a Fisher Bullet Space Pen, this is the refill you need. You will be delighted with the performance of this pressurized refill, best known for its trip to the moon. Select from eight colors in the medium point size, and standard colors in fine and broad point. You will also see the optional Bullet pen clip here. This comes in three colors, gold, silver or matte black to either match or accent your Space Pen.