... batteries inside or external batteries ; pure sine wave 220V 380V IntroductionDX6K-DX20KL, adopts the double conversion online ... or damped oscillation, high-voltage pulse, voltage fluctuation, surge voltage, harmonic distortion, clutter immunity, and frequency fluctuation ... batteries inside or external batteries pure sine wave 220V 380VAC Specifications Environments: Office| Server Room| IndustryInput ...