YouCute 3.7V 450mAh Official Battery for UDI U27 U941 U28-1 U941A U841 U843 U842 Kestrel U28-1Transmitter RC Quadcopter Drone Spare Parts package include : 1pc 3.7V 450mAh battery For UDI U27 U841 U843 U842 HD+RC drone For UDI U842-1 U28-1 fpv transmitter Over charge protection, Short circuit protection Rechargeable up to hundreds of times