This is the first time on Torchwood that Jack's past as a Time Agent has been referred to. No one has ever questioned him about his wrist-strap or where it came from (although he has obviously aumented it from its original functions). In Dr Who Series One Jack was introduced as a Time Agent and assumed the Doctor and Rose were also. But until now, it had never been mentioned on TW. Nor has Jack explained it any further than what is revealed in this episode.
