A UPS: https://www.apc.com/us/en/product-range/61883-backups/ https://www.apc.com/us/en/product-range/61883-backups/ Note that this will only carry it until th

A UPS: https://www.apc.com/us/en/product-range/61883-backups/ https://www.apc.com/us/en/product-range/61883-backups/ Note that this will only carry it until the UPS batteries run flat, so a power outage of a duration longer than the runtime on the batteries will still shutdown the computer. Larger battery sizes (also more expensive) will run for longer duration's.