A Project 705 class submarine
Project 705 (or ) was a type of military Alfa-class submarine used in the mirror universe on Earth during that planet's 20th century. One of these submarines was successfully seen torpedoing a Type VII submarine. ( : " ENT " In a Mirror, Darkly opening credits)
Although not mentioned by name, the Project 705 submarine (pictured, right) appeared in the opening credits, indicating the craft was manufactured and used in that universe. It was re-purposed footage from the 1990 Paramount Pictures Earth Cold War movie , albeit flipped – or "mirrored" if you will. The The Hunt for Red October studio models for this movie, including that of Project 705, were built by Gregory Jein, Inc., subcontracted by Boss Film Studios, and for which Jein had to temporarily suspend his commissions on Star Trek: The Next Generation . ( ;  Cinefex , issue 42, pp. 10-21) Since the actual Soviet-made Alpha -class only became commissioned over two decades after the World War II German Type VII had become obsolete, it torpedoing one – in our universe at least – constituted an anachronism.