Location Earth Tags.

These are Location Earth Tags. From the website:

"In case of alien abduction these dog tags may save your life. The crucial data an alien will need to get you back to Earth is die stamped into these dog tags."

They even have a money back guarantee:

"Should you ever be abducted by aliens while wearing Location Dog Tag and not returned safely to Earth you will be entitled to a full refund of the purchase price"

For real. It's the perfect match for your tinfoil hat! Link