Scarlet Lime pen that is supposed to write over practically anything. As much as I looove Pitt pens, I've ruined many of them by writing over acrylic paints. I doodled some coneflowers over a envelope that was printed with acrylic paints on the gelli plate. So far, so good! I hope these pens are as good as they say, and they just might be the answer to the pen problem. I'll still stick to Faber Castell Pitt pens for drawing and watercolor sketches...I love the Indian ink.