Micron Pigma Pens contain pure pigment in a felt tip! They are excellent for drawing, graphics, documents, outlining and lettering work. Waterproof and chemical proof. On decorative painting projects, for best results spray with a matte varnish after using so that the ink won't smear if varnish is brushed on. Note: When not using these pens ensure that the cap is on tight. These pens have a felt tip so remember not to press too hard or the tip may bend causing ink flow to stop.