RESEARCH TRIANGLE PARK, N.C. (WNCN) – If you’re heading out on a boat or to the beach this summer, you’ll likely have a life jacket.

But you may not have known that most of those life jackets are tested in the Triangle.

If you look closely at the inside of the life jacket, you’ll likely notice a marking with the letters “UL.”

It stands for Underwriters Laboratories and it means the life jacket has been tested to meet safety standards.

UL’s facility at RTP tests all life jackets no matter where in the world they are manufactured.

Different types of personal flotation devices go through different types of tests. The first measures how quickly it can be put on. Another ensures it will stay on when someone jumps into the water with the arms above the head.

A third test determines how far above the water the device holds a swimmers mouth.

Safety standards are constantly being reviewed and updated.

“Our tests are in a constant state of flux,” explained John Drengenberg with UL.

UL Engineer Maury Turner added, “The authorities having jurisdiction like the coastguard and UL from what we see from our testing here, we all have input into making the standards safer and they have changed over the years to improve.”

Once a life jacket passes the tests, it’s given the UL mark.

For many, that means a little extra confidence.

“It does it makes me feel better to know that it’s safe,” said Ashley James, whose daughters and nieces use life jackets when swimming in Falls Lake.

“I can’t see the bottom. I don’t know if there’s a quick drop off, so in the lake I feel more comfortable with them wearing the life jackets,” she added.

Once a life jacket passes the tests and receives the UL mark, UL continues to follow up by visiting manufacturing plants to make sure the life jackets still live up to the standards.