The vanishing pen is used to make temporary markings on fabric. This purple version is meant for light colored fabric.
Markings disappear in 2 to 14 days, depending on the fabric. Marking will disappear faster in textiles made from natural materials.

Tip: Make a test marking to make sure it vanishes completely when you make markings on the right side of the fabric

How quickly the marks fade depends on the colour of the fabric, humidity and PH value of the fabric...