These are not for trade or sale
Notice the casino number 135...Harrahs Rincon San Diego

The top card has a "glittery" surface, while the middle card is flat in color.

The bottom card I found left behind in a slot machine when Harrahs Rincon first opened. I saw the slot mechanics use them to identify themselves when they opened the machines for repair or refills. Of course the new casino has all TITOs now, and I don't see them using these cards anymore. The back is blank with a magnetic stripe.