The APC Line R is a microprocessor controlled tap changing power conditioner, which automatically corrects brownouts and overvoltages, and stabilizes chronic line voltage variation. Line R also provides multi stage surge suppression and full time EMI/RFI filters to handle all the problems your equipment is likely to face. A voltage meter on the Line R's front panel displays the relative input voltage level and alerts you to low or high voltage conditions. Line R automatically performs self tests, and its "adaptive mode" also senses and corrects frequent tap changing, thereby reducing wear on the relays for a longer life span and quiet operation.