Uninterruptable Power SupplyEdit
A UPS or Uninterruptable Power Supply is a peripheral that delivers a battery-backed and surge-protected supply of electricity to a computer (and possibly its other peripherals as well) in the event of a power failure or other irregularity in the input stream.
Example UPS
An example UPS is this model that I’m currently using with my iMac. I have been by and large quite happy with it, although it does occasionally fail to protect the machine from power outages. I am not sure how much money it would be necessary to spend to get a UPS which actually does reliably protect the machine from things like local blackouts, brownouts and trivial incidents like the wall power socket being disrupted.