The Acer KT.0030G.020 is a replacement battery pack for compatible Acer laptops. Its AP18C 3S1P designation describes a three-cell polymer configuration.
With a stated capacity of 4343 mAh, it is intended to restore battery operation in supported models. Acer service documentation identifies it for the SF314-512 assembly; a parts listing also names SF314-41 and other compatible systems.
Listed examples include SF314-59, A315-23 and CB314-1H. Check the laptop model against compatibility information when choosing a replacement.