Maintains usable 220V–240V nominal output to sensitive electronics during severe brownouts and overvoltages. Prevents surges and spikes from damaging circuitry. Filters out potentially disruptive line noise. Ideal for computers, routers, modems and home theater components. Corrects under- and overvoltages in 168V–278V range. Protects against spikes with 340 joules of surge suppression.