Protect electronics from damage caused by outages by ensuring your backup is operating properly. Replacement cartridge features hot-swap functionality for continuous power flow, even during battery changes. Safe, reliable and maintenance-free, it features the absolute minimum number of connections, keeping installation quick and easy. Cartridge #2 (RBC2). Battery Type: Sealed Lead-Acid; Battery Size: RBC2; For Use With: APC® BE500U, BK200, BK250B, BK250I, BK280B, BK300C, BK300X116, BK350, BK400, BK400B, BK500, BK500MC, BP280, BP280C, BP280IPNP, BP280PNP, BP280S, BP280SX116, BP420, BP420C, BP420IPNP, BP420PNP, BP420S, BP500CLR, BP500UC, BP700UC, SP500DR, SP500DRSU420NET; Belkin F6C325-SER, F6C425-SER, F6C500-USB, F6C525-SER, F6C625-SER, F6C650-USB, F6C650-USB-MAC, F6C500-USB-MAC; Material(s): Lead-Acid.