A tower has no internal reserve. The moment the supply at the wall stops, everything above the power supply stops with it, including whatever the machine was part-way through writing. A desk-side uninterruptible supply exists to remove that abruptness. It holds the output steady through the dips and flickers that never make the news, and when a real interruption arrives it keeps the machine alive long enough to finish what it was doing and close down in order.

Choosing one comes down to three numbers rather than a brand. The watt rating decides what you may attach, the battery decides how long you have, and the transfer time decides whether the machine notices the changeover at all. Everything else on the specification sheet is packaging. Evetech ships these from our Centurion warehouse, with major centres normally reached in one to three business days and regional addresses in three to five.