I get them at Harrah's Total Rewards Club. It's a miniature copy of a slot card and attaches to the slot card with a chain. After the slot card is placed into the card reader in a slot machine the mini card dangles from the chain. This particular card doesn't have a hole because I asked them not to punch a hole into it. Back then no one questioned how I was going to attach the dangle :

This is an enlargement of the dangle:

Here's my collection of Harrah's dangles. Both sides are shown:

I'm looking for Gold and Diamond dangles dated 2003 (if any were made) and any not pictured here.