When your voltage stages are unstable (ie: power stays on, but the actual voltage stage varies a great deal through the 220V conventional), then I believe that's the kind of situation where an AVR is helpful. Should your Listing composition doesn't match the bundle naming as per the sample over, https://proud-pira-group15813.dgbloggers.com/34241202/ups-uninterruptible-power-supply-things-to-know-before-you-buy