UPSBatteryCenter compatible replacement battery pack for APC Back-UPS XS 1000 XS1000 100% Compatible Battery pack for the APC Back-UPS XS 1000 In-Stock and Ready for Immediate Shipment - 1 Year Warranty included! For use with UPS model #: XS1000 (Make sure this is the exact model #) Arrived assembled and ready for use - Hot Swappable, No Downtime Required Manufactured & sold exclusively by UPSBatteryCenter