APC REPLACEMENT BATTERY CART FOR BK250/280/400/420 BP2 - RBC2
APC Smart-UPS 420/620 User's Manual - APC Media
Mighty Max Battery 12V 8AH Battery for APC BackUPS Pro 350U 420 420C Rechargeable Sealed Lead Acid 1280 Backup Power Batteries in the Device Replacement Batteries department at Lowes.com
Amazon.com: SPS Brand 12V 8Ah Replacement Battery for APC Smart-UPS 420 SU420INET UPS Battery : Health & Household