It's called FriXion gel pen.

Thank you. I learned a lot.

I use them all the time. Just love it.

I thought I read on this board that these pens do show up again once the fabric is cold. I will have to look it up.

I did and I guess I was wrong...here one link that did a test.
http://www.quiltingboard.com/t-129694-1.htm

They are great and I use it all the time!
What do I put a warning: only in some fabric with the heat of the iron is the color mark of the pen, but it is a white mark on the web that will not leave.
Should always test on a piece of fabric that will be used to see if you leave or do not check before dialing your final project.

You might think twice about using these pens. Read this article
http://jovitaspatchwork.blogspot.com...-gel-pens.html

Thanks for the info. I'm in Scottsdale and go to the one in Mesa.

Robyn

You find them in office supply stores or at least that is where I find mine. They are made by Pilot Pens

I have these pens! They are great!!