Those are Molotow ink pens.
The ink is alcohol based and was designed for black construction paper.
On plastics and other hard mediums they look great, for about a week.
As long as you don't touch it or look at it in a strange way. Its pretty delicate stuff.
The pens also don't hold up for very long and the ink tends to "pickle" itself after several months in the pen.
They also tend to be a bit pricey, which is why I'm looking forward to trying the new stuff.
