The packaging states the pen is "ready to use" out of the package. No lie. The pen is a nice weight, and writes without skipping.
The saying from a fortune cookie, "Keep your face to the sun and you will never see the shadows" had me taking the pen for a spin in my journal. The pen makes a medium weight monoline, and the ink dries quickly. However, the ink is not waterproof. I used colored pencils to color the sunflower even though I would have preferred to use watercolor pencils. Since the ink is not waterproof, with a brush and water adding a shadow would be easy. Will have to play with that sometime.
While I wouldn't use the pen for fine work, it's portability and ease of use will make it a fine addition to traveling with a journal or working away from the studio. And, as soon as the pen runs out of ink, I'll try taking the pen apart to see if it can be refilled.
Have you used the Bic disposable fountain pen?