This is an APC Smart-UPS rack-mount uninterruptible power supply rated at 5kVA, a step up in capacity from smaller Smart-UPS models, suited to protecting a heavier load of rack-mounted servers and network equipment. As a line-interactive UPS it continuously conditions incoming mains power and switches to its internal battery the moment it detects an outage or a voltage sag, keeping connected equipment running through short interruptions or bridging the gap until a generator kicks in or a controlled shutdown can happen. Its rack-mount form factor is built to install directly into a standard server rack alongside the equipment it protects, rather than sitting on the floor.