These amazing little fountain pens are one notch above a disposable pen and are refillable. They come with a small capsule containing three cartridges of ink that match the color of the pen. You can buy the pens in groups or individually. Individually, they cost about four dollars each with $1.25 in shipping from Japan on Ebay.
As the name indicates, these are very short pens measuring 4 1/16" inches (10.3mm) with the cap on and 5 inches with the cap posted. The girth is a comfortable 9/16 inches (1.4mm). The size and shape of these pens and the fact that they post to a normal length make them ideal pens to throw in your pocket or knapsack while you are out of the house/office. You don't have to worry about scratching them or losing them as you do with other fountain pens. This is really nice for the summer, when you don't have a breast pocket to safely store a better pen.
The irony is that the Pilot Petites write so amazingly well, that you are inclined to use them even at your desk where the more expensive pens are looking down disapprovingly. In fact, these four dollar fountain pens write much better than a couple of $100 pens that I have.