black, blue, red, turquoise, purple, navy, pink, & green The Power Of STEM: The science behind FriXion erasable pens embodies the principles of STEM and enables exciting hands-on demonstrations ...

There are some workarounds to this problem, but not many of them are as smooth an effortless as this one which uses erasable pen ink to add colors to the filament on the fly. Erasable pen ink is a ...