Sample this

I have a card type you may not be familiar with here:

2003 Donruss Elite
Back to Back Jacks
BB27 Adam Dunn / Austin Kearns
Dual Game Used Bat Card

I hear ya.
What's so great about this card?
Well, it's a SAMPLE card. Not the type found in sealed Tuff Stuff's ad Becketts in those days but the prototype sent by Donruss for approval from the MLBPA before full production could begin. Even though it does not say so on the card this is the only one in existence.
And as you can see Dunn is in the process of smashing a tater and Austin has just walloped one out o da park for a quadrangular trot.