183560101 is a test instrument Phasen Faspenna with a casing of heli-insulated material that can be used to locate breaks in cables outside the insulation.
Check fuses in power stations and plug cabinets, identify live wires in junction boxes, etc.
It indicates for complete fuses in central, voltage in ungrounded wall outlet, and live conductors outside insulation.
Live conductors outside the insulation (unshielded cables)
It has a sensitivity of about 4mm from a conductor at 230VAC and an overvoltage of CAT III 1000V.