Plasti-Disc
From Tardis Wiki, the free Doctor Who reference
A Plasti-Disc was a security device used for the Braxiatel Collection. It was approximately two imperial inches in diameter and pink. The discs, whilst doubling as an invitation to see the Collection, were also a security pass, and were keyed to the owner's bio-emissions to avoid them being given to other people or stolen. They would open any door in the Collection that the owner had access to.
Wolsey had his own disc, which was fastened to his collar. It had a built-in mass detector which stopped anyone from getting into the Braxiatel Collection by carrying him. (PROSE: The Doomsday Manuscript)
