CyberPower’s CP900AVR has a simple-to-use interface with just two buttons (electric power on/off and mute) and 4 indicator lights (showing if the device is turned on, once the battery backup kicks in, when AVR is activated, and when there’s a power overload) about the entrance with the unit. Photo: Michael https://bobo-shabu-and-grill61581.blogars.com/35123227/the-2-minute-rule-for-ups-battery-lithium