This religious artifact is called an Electropsychometer or E-Meter. (Electro-psycho-meter from electrometer, a calibrated device used for measuring extremely low voltages and psyche, the human soul, spirit or mind.) The E-Meter measures the spiritual state or change of state of a person and thus is of enormous benefit to the auditor in helping the preclear locate areas to be handled. The reactive mind's hidden nature requires the use of a device capable of registering its effects—a function the E-Meter does accurately.