This is the I.S.S. Enterprise from the mirror universe seen in the classic Star Trek episode Mirror Mirror. In that episode, while Kirk, Uhura, Scotty and McCoy are beaming up to the Enterprise, an ion storm screws up the transporter exchanging these four with their evil twins from the evil mirror universe. The episode follows Kirk and crew as they try to get their way back to their own universe. You see little of the evil counterparts on our Enterprise. This universe was also visited in an Enterprise episode suggesting that the Defiant from the Tholian Web episode faded into the same universe. This Enterprise is a bit different from the standard Hero Enterpris because they used stock footage of the early second pilot model in reverse for the ship. What a great way to distinguish the difference between the two ships. I have the Diamond Select version of this ship because it helps demonstrate the differences in the second pilot model and the final shooting model.