indelible voting ink election cheatproof marker pen 1. Indelible markerfor election or vaccination, 3ml or 5ml 2. With sliver nitrate, can't be washed by daily detergents 3. Stain at least 96hours. When the ink tipped on the finger, turn to brown color finally; 4. Violet color is the best performance 5. Silver nitrate ink mostly to be used for voting and election,the content of the silver nitrate could be 5%, 10%, 15%, 25%...It can be according to your require, and the more content of silver nitrate contain, the better effect it will be. 6. Rich experence in election product, export the ink. for Iraq, Tanzania, Afghanistan, Nigeria, Congo, Malawi.