CyberPower’s CP900AVR has an uncomplicated-to-use interface with just two buttons (electric power on/off and mute) and 4 indicator lights (showing in the event the device is turned on, when the battery backup kicks in, when AVR is activated, and when there’s a power overload) on the front of the unit. https://mixed-martial-arts31739.liberty-blog.com/36441608/new-step-by-step-map-for-battery-ups-csb-hr-1221-wf2-12v-21w