500 amp-50 mV Shunt: For systems with maximum current 400 amps continuous with no overloads, or 300 amps continuous with up to 5 minute overloads to 500 amps max. It allows amp readings as low as 0.1 amps. They are suitable for virtually all systems with moderate or large sized inverters. Size 3-1/4 by 1-3/4 inch base, 1-7/8 inches in height.