Optima Fixed Tip 14 Feather Edger. This pen design is from Bob Guge. Great for burning in primary's or anywhere you would otherwise use a pen to burnish or depress wood. Instead of depressing and moving the pen for each area along a line "like you would do with other pens", this pen is designed to act like a ski. Just put it at the start of your feather edge and follow it. Saves you a lot of time. Tip for #14 & #15: These pens do not have a sharp edge. To eliminate any metal that has rolled over the edge from polishing, place the edge perpendicular to a fine stone and move over surface once. Remember this pen's edge acts like a ski and like a ski its edge has to be square in order to work properly.