GUEST: I've brought my grandfather's watch. He was a naval aviator.

APPRAISER: This is a 1970s Rolex. It's called a GMT, which is Greenwich Mean Time. You have a second hand there that's red that rotates every 24 hours. So when you were a pilot you could time two locations. And this is what's called a 1675 reference number. And it hasn't been polished. It has the original dial. GMTs are super sought after, especially early '70s ones. A watch like this would probably retail for about $5,000.

GUEST: Wow, that's awesome.