Removable marking pen that's great for marking almost any material. Works especially well on leather, metal, glass, plastic, cardboard, and bricks.

The pen leaves a rubbery surface that's easy to wipe off with mechanical rubbing, no solvents needed. The double-ended tip can be flipped back around, so you've got a sharp tip again for use.
Features:

Removable
Waterproof
Double-ended tip