$29

Used Belkin Surge protection plus pc battery back-up for home computer system. The 12volt back-up battery needs to be replaced, otherwise the machine works flawlessly. The replacement battery costs from $12 to $13 on eBay or amazon or you might go to a local vehicle&motorcycle parts to get it. The four outlets inside the white squared line which indicates surge and battery back-up protection need a new replacement 12voult battery in order to work. It is pretty easy to replace a new battery, just press down the horizontal two inches long plastic tap on top of its compartment to open the cover door. Then carefully pull out the old one from the compartment as you see in the picture and dis-connect(gently pull back) the black&red electrical wires metal contacts on top and replace with a new one. With a very powerful 12volt back-up battery,and it provides more than an hour of power that's more than enough time for you to save all the important files and turn off your computer.Peter(415)948-0966The network reply link will not work ! Please contact Peter at the above phone number or e-mail:  pdao01@yahoo.com Will be answered next day.  Thanks!