One goes into one of your boots, and the other goes on the chain around your neck, when you go to war. In garrison we wore both around our neck. I would NEVER accept an implant. In 94 the army drew my blood during inprocessing to go into the DNA database, so no problem there. I do not know about the active duty cards now, but on the back of my VA I.D. is the magnetic strip that is readable by a machine and shows my information. TX has the same thing on the drivers licenses and TX state I.D. .