Line-R 600VA Automatic Voltage Regulator Automatic voltage regulation for protection against brownouts and overvoltages. - Automatic Voltage Regulation (AVR) Automatically steps up low voltage and steps down high voltage to levels that are suitable for your equipment. - Resettable circuit breaker Easy recovery from overloads; no need to replace a fuse. - Lightning and Surge Protection To prevent damage to your equipment from electric power surges and spikes.