The model GF312D1 is a precision 0.05% AC energy meter accuracy testing instrument with 12A/600V and 120A/600V range, mainly used to test single phase and three phase energy meter error on site, measure all various of AC parameters and CT ratio & phase error, it is also as three phase reference energy meter in the laboratory. Mainly using test single phase or three phase electricity meter error on site. GF312D1 handheld energy meter calibrator is an ideal test tool for the metrological service of electricity power utilities.