Temporal conduit

From Memory Alpha, the free Star Trek reference

The temporal conduit was a device that allows travel through time.

A group of Na'kuhl led by Vosk escaped a near-defeat in the Temporal Cold War, using stealth time travel technology to reach an alternate 1944 Earth. There, they constructed a temporal conduit in New York City in an attempt to return to their own 29th century. However, they were forced to use local materials, that they secured through an alliance with Nazi Germans. The primitive technology used made the machine enormous, and the Na'kuhl had difficulty keeping the conduit stable for more than a few seconds. After several failed attempts to operate the temporal conduit, the Na'kuhl were eventually successful, although the NX-class starship Enterprise destroyed the device moments before the Na'kuhl could enter it. (ENT: "Storm Front, Part II")