LS Accessories BL-5J Li-ion Batteries for the Nokia Lumia 520 (AT&T), Nokia Lumia 521 (T-Mobile), Nuron 5230, Xpress Music (5800), Nokia C3, and N900 plus Universal Charger with USB Port Batteries are compatible with Nokia Lumia 520 (AT&T), Nokia Lumia 521 (T-Mobile), Nuron 5230, Xpress Music (5800), Nokia C3, N900 and other phones using the Nokia BL-5J Battery 1350 mAh High quality Lithium Ion battery that charges to its full capacity for over 500 cycles Grade A batteries with Dual IC protection to ensure safety; Battery Voltage: 3.7 Volts Battery Energy Content: 5.00 Watt Hours Universal Charger with USB Port that can charge your 2nd battery and cell phone at the same time Charger Input: 100-240V, 50/60HZ, 0.1A; Output: DC 4.2V, 300mA; USB Output: 5.2V 500mA