Angelus Dye Liners "component pens" are available in two sizes - fine and broad point.
You can fill these pens with dye color of choice, and then use them to apply small amounts with precision.
You'll want a separate Angelus Dye Liner pen for each color used to do detail work. These Angelus Dye Liner Component Pens are great for custom work.
Directions for use:
Fill the reservoir with Angelus Brand Dye of your choice.
Put end-plug in place (you do not need to insert all the way)
Hold pen - tip down - and wait for the dye to saturate the entire insert.
Use with CAUTION. Dyes are meant to be PERMANENT!
Keep away from children. Content (dye) is FLAMMABLE