Frixion are probably the pens you saw. You can buy them in any stationary store for way cheaper than they sell them in the quilt stores, and you can get several colors - red, blue, and black. I have found that if you leave them on too long on some fabrics, they will leave a bleached looking line behind when you iron the color away. May or may not be a problem sometimes. That won't happen if you don't leave the pen color on for an extended period of time. And you can use a dry or steam iron to iron the pen mark away. I love them, I use them all the time.