CyberPower’s CP900AVR has a simple-to-use interface with just two buttons (electric power on/off and mute) and 4 indicator lights (exhibiting when the unit is turned on, in the event the battery backup kicks in, when AVR is activated, and when there’s a power overload) to the entrance on the unit. https://zanewtpje.p2blogs.com/35064563/how-much-you-need-to-expect-you-ll-pay-for-a-good-ups-battery-charger-13-8v