GENUINE APC UPS BATTERY REPLACEMENT: For optimal performance, use APC-branded replacement battery cartridges with your APC Smart-UPS, and check the product you receive to confirm it is APC-branded TESTED AND CERTIFIED RBC CARTRIDGE: Each APC Replacement Battery Cartridge (RBC) is tested and certified for compatibility to restore your APC UPS performance to original factory specifications MODEL-SPECIFIC COMPATIBILITY: APCRBC160 is compatible with APC Back-UPS Pro model BR1000MS (verify compatibility before ordering) WHEN TO REPLACE THE UPS: A new battery can fix most runtime issues if the UPS itself is still in good shape. If not, you may not get the expected runtime after installing a new battery, and it may be time to replace the UPS BACKED BY APC WARRANTY: Genuine APC replacement batteries are backed by a 2-year manufacturer warranty