This voltage transformer/convertor is safest way to use Korean Electronics in USA. Most people just use an adapter that fits the plug which is simply changing the shape of the adapter plug. But the plug adapter doesn't change the voltage of the electricity which can damage your electronics. North America uses 110V-120V, while Korea uses 220V-240V. This 3000w transformer/convertor converts the 110V-120V electricity into 220V-240V. Especially nowadays almost all electronics are advanced and have a computer like hardware inside, so it is crucial you use a convertor so the different voltage doesn’t damage the internal hardware.