... *Built-in Gyro YICHENGTIANJI-3.5 ch rc remote control helicopter rc with gyro,USB charged,indoor flight,Fuselage ... are super durable;- Built-in gyro offers the helicopter a nimble and stable flight;- Can charging by ... blue -Frequency:A,B and C-Battery for helicopter: 3.7V-150mAh li-po battery (included);- ... below! YICHENGTIANJI-3.5 ch remote control helicopter rc with gyro,USB charged,indoor flight