Most people adjust their watches and clocks according to the time displayed on their cell phone. But now you have a new guideline: the NIST-F2 atomic clock.

Built by the National Institute of Standards and Technology (NIST), the next-gen device will serve as the U.S. civilian time and frequency standard.

The most accurate clock in the world, the F2 could run continuously for 300 million years and never stray from the perfect time for even one second. By nearly eliminating small errors caused by background radiation, researchers have have made this clock three times more accurate than the current NIST-F1—the standard since 1999.

For now, NIST will run the F1 and F2 clocks simultaneously for comparison's sake. Both machines use a "fountain" of cesium atoms to determine the exact length of a second; they are just the latest in a long line of cesium-based atomic clocks developed by NIST since the 1950s.

As the institute pointed out, everyday technologies like cell phones, GPS satellite receivers, and the electric power grid rely on high-accuracy atomic clocks, which help move innovation into the future.

"If we've learned anything in the last 60 years of building atomic clocks, we've learned that every time we build a better clock, somebody comes up with a use for it that you couldn't have foreseen," NIST physicist and F2 lead designer Steven Jefferts said in a statement.

NIST carries a heavy weight, providing timing and synchronization measurement services for a number of users, including to time-stamp hundreds of billions of dollars in U.S. financial transactions. NIST time is also circulated via the Internet Time Service, which receives 8 billion requests per day to sync clocks in computers and network devices.

"When you can do something better than the earth gives you naturally with its rotation, then you go ahead and start down that road," Jefferts said of his work on the atomic clock.

But the U.S. can't expect to keep the ridiculously accurate machine all for itself. A second version of NIST-F2, dubbed IT-CsF2, will be operated by the Istituto Nazionale di Ricerca Metrologica (INRIM), NIST's counterpart in Turin, Italy.

Check out the science behind the F2 in NIST's video below.