I was looking through my casino postcards (for something else) and came across this unusual postcard --
Golden Nugget Laughlin logo on a 3x5 postcard. Made from a thin copper sheet; stamped / 3 dimensional.

Per back of card, it's a "Kopper Kard"; put a stamp on it and mail. Must have been approved for going through the USPS system at that time (est. 15-20 years ago)? Today, seems that it would have trouble surviving the mail sorting systems of today.

Just an oddity. Enjoy.