not much to them. Card stock - could be run on most printers... Don't think they are going to be looked at as a 'proof' card much. More of a record what batch you got in case there are issues. Also when they figure out how long the shot is good for the card will show when you need a booster. At work they are giving us a $25 gift card for showing our card that we got shots. Think that was a way to ask without violating Hippa...
