Amazon.com: Replacement Battery for Back-UPS CS 350 BK350 - UB1290 Universal Sealed Lead Acid Battery (12V, 9Ah, 9000mAh, F1 Terminal, AGM, SLA) - Includes Two F1 to F2 Terminal Adapters - CP1500AVRLCD :
APC CS 350 Battery UPS Surge Protection Back Up Power Supply 120V (No Battery) | eBay