CyberPower’s CP900AVR has a fairly easy-to-use interface with just two buttons (electrical power on/off and mute) and four indicator lights (exhibiting once the device is turned on, when the battery backup kicks in, when AVR is activated, and when there’s a power overload) about the front of the device. Image: https://kungfu84971.gynoblog.com/35365608/the-single-best-strategy-to-use-for-ups-battery-replacement