A clocking device from the mirror universe in 2375
A cloaking device is a form of stealth technology that uses selective bending of light (and other forms of energy) to render a starship or other object completely invisible to the electromagnetic spectrum and most sensors.
In 2155, the ISS Enterprise had acquired a Suliban cloaking device and used it to enter Tholian space. (ENT: "In a Mirror, Darkly")
In 2371, the Klingon-Cardassian Alliance had cloaking technology. They used the cloak to capture Miles O'Brien and the mirror universe version of Benjamin Sisko. (DS9: "Through the Looking Glass")
By 2375, the technology was unknown in our universe. Regent Worf arranged to have one acquired from the mirror universe. (DS9: "The Emperor's New Cloak")