UPS not only regulates power going into your equipment, it can help prevent data corruption for a safe shutdown or cover the transition to a backup generator.
TYPE: STANDBY switches to battery after it detects a mains power problem (milliseconds delay) ONLINE has an internal inverter and prevents even those millisecond delays
CAPACITY Take the Watts requirement and multiply by 1.4
This is to take
RUNTIME The amount of time you need electricity from the batteries
E.g. Rated as 850VA (full load) for 6 minutes or 425VA (half load) for 21 minutes.
APC Smart-UPS 1500VA USB & Serial
APC Smart-UPS 2200VA USB & Serial 230V