The Saltah'na clock was a time measurements device from the ancient Saltah'na species from the Gamma Quadrant.
In 2369, while under the influence of a Saltah'na energy sphere, Commander Benjamin Sisko built such a complex mechanical clock from its blueprints. (DS9: "Dramatis Personae")
Sisko kept this clock in his office on board Deep Space 9. (DS9: "The Maquis, Part I", "The Way of the Warrior")
In an alternate timeline, Jake Sisko kept this clock in his house in Louisiana on Earth. (DS9: "The Visitor")
Benjamin Sisko did some repairs on the clock in early 2372. (DS9: "Hippocratic Oath")