U839 Spare Part 2pcs 3.7v 150mAh Batteries with 1 USB Charger Cable for UDI RC U839 Nano Quadcopter Replacement batteries,perfectly compatible with UDI RC U839 Nano Quad copter. 3.7v 150mAh lithium battery,high quality and rechargeable performance. Durable and pratical battery, rechargeable with long life using. Additional USB charging cable,more convenient for you to quick charge multiple batteries. Package include: 2pcs U839 batteries+1pcs USB cable