Crompton electrical moving-coil panel meter, England. A sensitive laboratory or switchboard instrument calibrated from 0–15 units (likely milliamperes or volts depending on external shunt or resistance). Marked with specifications “5 ohms, 75 mV, 15 mA” and “Ext. shunt leads 0.05 ohm,” indicating use with an external shunt for accurate measurement. Such meters were fitted to electrical test benches, power stations, or research equipment. Mid-20th century, c.1930s–1950s.
