Here's why:

* Skinny Pen Shape: Styluses are designed to resemble pens for a familiar and comfortable grip.

* No Ink: Styluses are used for touchscreens, not writing on paper, so they don't need ink.

There are many different types of styluses, some with a rubber tip, some with a disc tip, and some with a specialized tip for drawing.

Let me know if you have any other details about the device you're thinking of, and I can try to narrow it down further.