CyberPower’s CP900AVR has a simple-to-use interface with just two buttons (power on/off and mute) and 4 indicator lights (showing once the unit is turned on, once the battery backup kicks in, when AVR is activated, and when there’s an influence overload) on the front in the unit. Picture: Michael Hession https://edgarfgcvl.educationalimpactblog.com/57817214/the-2-minute-rule-for-ups-battery-lithium