CyberPower’s CP900AVR has a fairly easy-to-use interface with just two buttons (electrical power on/off and mute) and 4 indicator lights (showing when the device is turned on, when the battery backup kicks in, when AVR is activated, and when there’s a power overload) on the entrance from the device. Photo: https://taifudo-bodyguard18395.blogunteer.com/35252875/the-smart-trick-of-battery-ups-9ah-12v-katzuni-kz12v9-that-no-one-is-discussing