The Blue Sea DC Analog Ammeter displays amperage (0-50A) on your marine equipment. Easy to read characters. Senses and powers from an included, external, DC shunt with a 2-wire connection. Backlight requires separate 12V or 24V DC connections and operates at 16 mA @ 12V DC and 20 mA @ 24V DC.• Meter Current: 1 Milliampere @ full scale• External Shunt: 50 Millivolt @ meter full scale Includes external DC shunt | DC Analog Ammeter + Shunt, 0-50A