The APC SURT192RMXLBP2 is a rackmount extended-run battery pack for APC's Smart-UPS RT XL-series UPS units (SURT15KRMXLI/-CC/-CH, SURT15KUXI, SURT20KRMXLI/-CC/-CH, SURT20KUXI), used when a data centre or server room needs longer battery runtime than the UPS's built-in battery alone can provide. At 6U and rated for 3840 Volt-Amp-Hours of capacity, it slots into the rack alongside its matching UPS to extend how long connected servers and network equipment stay powered during an extended outage or load-shedding event, rather than only bridging a brief power interruption. This is an accessory battery module, not a standalone UPS - it must be paired with one of its listed compatible Smart-UPS RT models.