CyberPower’s CP900AVR has a simple-to-use interface with just two buttons (electricity on/off and mute) and 4 indicator lights (showing once the unit is turned on, when the battery backup kicks in, when AVR is activated, and when there’s a power overload) around the entrance with the unit. Photograph: Michael Hession https://fernandop7mh4.bloguetechno.com/the-best-side-of-ups-battery-replacement-71445712