Can be used for upper making or any sewing project. The mark visible by eye, but under UV light (blacklight) is where really shines - literally! The markings disappears easily with a little heat, so cleaning the upper doesn’t need any more solvents, rubbing or much effort. Silver pens work great but these are cooler. Price is for set of 3.

Caution: Always try on a sample first. Do not use directly on the final product without prior testing. Product can leave residue when pressed hard on the surface or if the surface is very light colored.