Sudden power outages not only cause you to lose your work, but can cause hardware failure and loss of data such as photos, work documents, and business records. A battery backup prevents this from occuring by instantly switching to battery power in the event of a power outage. Belkin will repair or replace any equipment damaged by a surge, spike or lightning strike while properly connected to a Belkin Battery Backup, up to a maximum value stated on the front of the package. Belkin will replace, free of charge, any Battery Backup that is defective or expires after protecting your electronic devices. Warranty includes battery.