is a cool drone but have some defects. One of them is the easy to loose 5D button
of the controller. Some users reported problems just after two days of flight.
DJI warranty will replace the whole controller to a brand new (not very ecologic), but you will not have the drone for at least three weeks.
So this is a 3D printed design of the 5D button to replace and put yourself in the controller.
The 5D button is not very common used, but can be usefull to make zoom in case that you want to see some details in the image.