I have the same question as a lot of the other comments here. I am not quite sure I understand the point of this.  I think it is cool.  It reminds me of the old Hypercolor shirts back in the day where people would walk around with handprints all over them.  I don't quite understand why you would need this tough.  Maybe so you know ahead of time if your bills are going to be all wet and nasty?   Nice hunt none the less...