If you ever see the four letters “SSSS” printed on your boarding pass, you’re going to be spending more time at security checkpoints.

The four letters stand for “secondary security screening selection.”

It’s a designation alerting security checkpoint personnel to pull you aside for enhanced security screening.

But how did those letters find their way to your boarding pass in the first place?

It’s based on an old and antiquated profiling system that dates back 20 years. You get the four “SSSS” if you made your plane reservation within 24 hours, bought only a one-way ticket or paid cash for your flight.

So get ready for a full search with portable metal detectors, including a full-body pat down and all your carry-on bags opened, emptied and inspected.