An ID Dart was a rocket launcher that was capable of deploying a portable ID Portal. They were launched and embedded themselves into walls where they opened up into a Portal format thus allowing for an instant Portal for use. They were at times meant to be disposable as they exploded after use.

Liam used it once more in order to get into Dr Emilly Kings hideout and to allow her to escape from Volunteer forces that were intent on her capture. (Episode: Abduction) Vorjak used one in order to get his wife Lili Marquette and daughter Ariel to escape. After departing, the portal exploded in order to prevent others from using it. (Episode: The Forge of Creation)

The devices had been seen in Season 3 on numerous occasions but were named in the first episode of Season 4.