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Invention #249 - Sub-Photonic Spectro-Analyzer (Fantastic Four vol.1 #347)

Every person has a unique energy signature based on their body’s bio-electrical matrix.  People with powers might have an even more distinct signature.  Reed’s build a hand-held device that can quickly identify a person’s energy signature.  (Too bad in this case, it’s being used as part of a deception…As you can imagine, Reed’s not really dead.)

http://en.wikipedia.org/wiki/Bioelectricity