The Quantum Mirror was a device which allows people to travel into an alternate reality and was created by the Ancients. It was controlled with a separate control remote, which allowed the user to "dial" to different dimensions. It was found on P3R-233 by Dr. Daniel Jackson.

Once activated and a selected reality was chosen, the user could watch that universe via the glass of the mirror, like watching a movie on a television screen. If they touched the mirror, the user would be engulfed in energy and transported to the chosen reality. Only with the use of a Quantum Mirror of the other reality, could the user return to his original universe.