This provides an uninterruptible power supply (UPS) in the event of power cut to allow time to close down your computer.
Believe to be working but I'm unable to test it since the battery is now dead. A new battery can be found on eBay for under £18.
Collection from Matlock.
apc cs 350 ups (Matlock DE4)
This offer has been gifted to someone and is no longer available.