A vibra-knife was a hand-held weapon that functioned somewhat as a knife and was used primarily for close-up work – cutting away clothing or cutting into a person's body. Particularly precise cutting could be done with a vibra-scalpel. It required a power-pack in order to function and when not powered on was referred to as "closed," possibly in analogy to a switchblade. A closed vibra-knife could be hidden within the palm of a hand.