APC Smart-UPS RT 20kVA Tower/Rack-mountable UPS reduces preventative maintenance service needs by monitoring the health and status of the external batteries and their expected runtime. This UPS features hot-swappable batteries which ensures clean, uninterrupted power to protected equipment while batteries are being replaced. It also increases availability by allowing a trained user to perform upgrades and replacements of the batteries reducing Mean Time to Repair (MTTR).