... Pulse Width Modulator, closed loop control system to ensure the machine is stable4.Excellent welding performance: little spatter, arc stability ... over-voltage, overheating, over-current automatic protection to ensure welding safe6.Weldable materials: electrodes for acidic, basic welding, stainless steel ... of CE, 3C, ROHS, stable to use; each machine paseed the test like shaking, old age, high low ...