BTI UPS Battery Kit; Replaces APC RBC2; Maintenance-free sealed lead acid; 100% compatible replacement battery for APC RBC2, BK250B, BK280B, BP280, BP280PNP, BP280BPNP, BP280C, BP280S, BP280IPNP, BK300, BK300C, BK350, BK350EI, BP350U, BP350UC, BK400, BK400B, BP420, BP420C, BP420PNP, BP420S, BP420IPNP, BE500R, BE500U, BK500, BK500M, BK500MC, BK500BLK, BP500U, BP500UC, BP500CLR, BR500, BR500I, CP15U48D, CP36U52, PCPER, PCPRO, SC420, SP500DR, SU420NET, SUVS420