Emergency Beacon
From Star Trek : Freedom's Wiki
Emergency beacons are large hand-held lamps that can be used to illuminate dark surroundings, similar to palm beacons and SIMs beacons.
The beacon can be modified to emit only certain wavelengths of light. In 2367, Data modified a emergency beacon to work on ultraviolet light. In order to do so, he had to replace the regular emitter module. (TNG: "Identity Crisis")
