Atomichron

The Atomichron was the world's first commercial atomic clock, built by the National Company, Inc. of Malden, Massachusetts. It was also the first self-contained portable atomic clock and was a caesium standard clock. More than 50 clocks with the trademarked Atomichron name were produced.^[1][2][3][4]

See also

• Chip-scale atomic clock
• Hoptroff London