Specifications:

1)marking ink used for election,can't be washed by water
2)violet color is good effect
3)sliver nitrate contending

Indelible ink is also called silver nitrate ink, since it can't be washed by water, it mostly to be used for voting and election, the content of the silver nitrate could be5%,10%,15%,25%.......It can be according to your require, and the more content of silver nitrate contain, the better effect it will be .

Item:   Indelible Marker Pen/Leather Marking Pen