Fob watch
A fob watch was a watch carried in the pocket, as opposed to being worn on the wrist. The First, Seventh and Eighth Doctors all regularly wore and used fob watches.
A crucial part of the Chameleon Arch looked like a fob watch. (DW: Human Nature, The Family of Blood, Utopia) "Chameleon Arch fob watches" once held the Time Lord essences of both the Tenth Doctor and the Master. Such watches were recognisable, as Martha Jones learned, by distinctive Gallifreyan messages on the obverse.
Upon meeting Jackson Lake and seeing his fob watch, the Tenth Doctor thought that Jackson might be an incarnation of himself. When the Doctor turned the watch over, however, it didn't bear any Gallifreyan script, and was therefore revealed as an ordinary fob watch. (DW: The Next Doctor)
