The APC Smart-UPS RT SURT20KRMXLi is a 20kVA double-conversion online UPS built for 12U rack mounting in a data centre or server room. Double-conversion online topology means the load runs continuously off the inverter, giving a clean, zero-transfer-time output regardless of mains quality — the standard choice for protecting servers, storage arrays and networking gear from load shedding and grid instability. This unit ships with the AP9619 Network Management Card already installed in its smart slot, giving remote monitoring, SNMP/web access and environmental sensor input. It supports additional SURT192RMXLBP2 external battery packs for extended runtime, and includes a cooling fan for sustained thermal load. Realistically bought by IT departments and data centre operators needing serious, scalable backup power.