Amazon.com: APC Back-UPS RS 800VA 230V India BR800-IN Battery - Replacement UB1290 Universal Sealed Lead Acid Battery (12V, 9Ah, 9000mAh, F1 Terminal, AGM, SLA) - Includes Two F1 to F2 Terminal Adapters :
Replacing Battery on Back-UPS XS & RS LCD Series | Schneider Electric Support - YouTube