Final answer:
An authorized device on the PMD for individuals in combat is a metal detector, used to locate explosives and weapons.
Step-by-step explanation:
A device that is authorized on the Personal Mobility Device (PMD) for an individual exposed to combat is a metal detector. This device is specifically utilized by soldiers to search for explosives and weapons. The information provided suggests that the context is military operations, where the use of a metal detector is crucial for the safety of soldiers operating in areas where there may be hidden explosive devices or weapons that pose a threat to their safety and the success of their mission.