Bio-damper

A bio-damper is a component that masks the bio-signiture of an individual. The dampening device could be as small as a ring. The Doctor gave Donna a bio damper so that she would by hidden by the Racnoss. However, bio dampers are proven inneffective against Huon particles. (DW: The Runaway Bride).

Martin Trueman had a Bio-damper to hide the fact that he the had Ancient Lights in him. (SJA: Secrets of the Stars)