The APC Replacement Battery Cartridge 123 fits selected APC Smart-UPS and Back-UPS models, restoring power backup capacity for home offices, small businesses and IT departments. This replacement battery cartridge has a lifetime of 3 to 5 years, offers safe and reliable support to the UPS and extends the useful life of your UPS. It comes fully assembled and includes easy-to-follow replacement instructions, making hot-swap installation simple.