Check out this amazing, erasable pen. The Frixion pen is a smooth writing gel ink pen with a little twist -- it is completely erasable! The Thermo-Sensitive gel ink is formulated to disappear with the erasing friction, leaving no trace.
The most amazing feature of the Frixion Pen is you can use it on fabric to trace on a pattern. Mark as hard and as dark as you wish. Once you have finished stitching, or if you make a mistake while marking, you can erase the marks. Simply take an iron to your fabric and the ink will completely disappear.
These pens have a fine .7 mm rollerball point.
henry l.