Note that this is a error with the DVD's case and is not actually seen in any episode.

I found this on the packaging for volume 5 on the first release of the Region 1 set (not the thin-packs). This may seem like a "trivial error", but to major fans of the show, it isn't. Okay, on the box for volume 5 of the original season 6 set, read the description for the episode "Memento". It says "SG-1 accompanies the X-53 on its maiden voyage into deep space.". The text continues for a few more sentences in your typical advertising way, but the point is; anyone who has seen seasons six through eight knows full well that the coolest ship in the galaxy is the Prometheus; formerly known as the X-303 (pronounced "three-o-three"). I have no idea how this could possibly be mistaken for "fifty-three". Whoever made this mistake could use some help from miracle ear, after all, this would be like typing on a Star Trek season "Captain James R. Kurt's missions aboard the Interprize..."