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 #35 (RBC35). Battery Type: Sealed Lead-Acid; Battery Size: RBC35; For Use With: APC® BE350C, BE359R, BE350R-CN, BE350T, BE350U, BE350U-CN; Material(s): Lead-Acid.