AC Doctor INC 5200mAh 6Cell Laptop Battery for Acer Aspire 5520 5920 AS07B31 AS07B41 AS07B51 AS07B71 Replacement laptop battery for Acer Aspire 5230 5235 5310 5315 5330 5520 5920 5921 5720 5920G 7520 6920 6930 6920G 7520G 7720 7540 7736Z-4809 AS07B31 11.1V 5200mAh black 204.80x68.27x20.00mm 216.1g. 10.8V and 11.1V is compatible, 14.4V and 14.8V is also compatible. Full compatible with your original battery, brand new direct from Professional Manufacturer. CE UL RoHS certified, safe use. 60 days no worry to return or exchange item, 12 months customer service warranty, US local dispatch. Please Note: Please make sure that the product shape and the battery part numbers listed in the description matches the battery part number on your original battery before you purchase.