In addition lubricates the pin! The other day I used it with the bag despite the bad experience once again at a point where the marker is no longer visible after sewing. And I have "eingesaut" me the flat bed sewing machine of my total. I had to play with a strong cleanser to get the bluish discoloration gone, which would otherwise be transferred safely to subsequent bright fabrics.
I find this pen is not recommended!
Then prefer the good old tailor's chalk. The available by now in various forms and also as a pin
