WATCH: Skimmer didn't scam this educated tourist!

You should probably know about skimmers. They're devices that crooks slip over ATM and credit card machines to steal your information.

Watch how one Washington-based senior technical services consultant for a cybersecurity company found one on a trip to Vienna with his family.

By habit, Ben Tedesco checked the card reader and found a custom made card skimmer that perfectly matched the ATM had been slipped over the machine.

Tedesco removed the skimmer and shared a close-up video of it. He also warned a woman who was using a nearby ATM, but it turned out her machine didn't have a skimmer.

Then, he notified police and shared notes with security companies there.