The model GF313 handheld three phase electricity meter field tester is a economical 0.2% AC energy meter accuracy testing device, mainly used to test three phase and single phase electricity energy meter error on site, measure all various of AC electrical parameters - U, I, P, Q, S, PF, F and CT ratio & phase error etc. And then it can check whether the wiring of the electricity meter is correct. GF313 electronic meter tester is an ideal electrical test tool for the metrological service of electricity power utilities. It has been widely used in more than 80 countries around the world.