Every time the Chameleon Circuit creates a new exo-shell to disguise the TARDIS a duplicate of the shell is stored in the Shell Room. A TARDIS that has done lots of travelling will have vast numbers of shells stored in the shell room. It should be noted that even if the Chameleon Circuit suffers a complete system breakdown (as many older TARDISes were prone to do if they didn't receive regular chameleon conversions) the Shell Room will continue to collect new unused shells every time the TARDIS materializes.
The following color code is used:
- Black: For information from the TV Series, including Dimensions in Time, and 1996 TV Movie.
- Blue: For information from the Novels and Audios including Target, Virgin, BCC, and Big Finish.
- Green: For information from 'licensed' reference sources such as the Technical Manual, Doctor Who Magazine, and the Role Playing Games.
- Red: For information from unofficial sources -The Faction Paradox series, behind the scenes interviews, author's speculation, and popular fan belief.
The TARDIS Technical Index is copyright Will B Swift.