Lopurs 3500mAh Rechargeable Li-Polymer Battery backup battery replacement for Nokia Lumia 1520 Brand new and high quality Li-Polymer battery for Nokia Lumia 1520 Best replacement for the original battery with comparable standby and talk time Use the authorized charger only Capacity : 3500mAh If you do not use the battery for a long time, please put it in a dry and cool place and make it full charged once every three months