I have always used the Pigma Micron 01 (0.25 line width) pen. These are available at most quilt shops. My quilt labels have held up well over the years and my quilts get used and washed. When I used to hand quilt everything, I would apply my label to the quilt back before I quilted it, so the label was quilted onto the quilt and couldn't easily be removed if the quilt was stolen. Now that I use a LAQer, it's not really an option. If you quilt your own quilts, I think this is a good idea. Sorry if I got off topic....Barb