CyberPower’s CP900AVR has an uncomplicated-to-use interface with just two buttons (energy on/off and mute) and 4 indicator lights (showing in the event the unit is turned on, when the battery backup kicks in, when AVR is activated, and when there’s a power overload) to the entrance of the device. Image: https://kameronyazyw.thekatyblog.com/34876265/not-known-details-about-ups-lithium-battery