APC Replacement Battery Cartridge #7 RBC7 for SU1000XL, SU1400, (RBC7)
Amazon.com: RBC7-UPC Replacement Battery for APC Smart-UPS SU1400, SUA1500, SUA750XL, SUA1000XL, SU1400NET, SU1000XLNET - Scroll Down for The Complete List of Compatible Models : Electronics