Replacement battery fits 11 Acer compatible models. Specifications: 4400mAh, 14.4V, Li-ion. Compatible with: Medion MD42200, L51, AOPEN 1547, AOPEN 1555, AOPEN 1556, AOPEN 1557 and 5 more compatible models. Replaces: Acer BTP-52EW, AOPEN 90.NBI61.001, AOPEN 90.NBI61.011, AOPEN 805N00005, AOPEN 40008236, AOPEN BTP-52EW and 14 more. Acer replacement battery designed for Notebook/Laptop devices.