This Ebay RC Pro Plus works with the Mavic series of drones because the seller has modified the operating system. He changed it from the OS that runs the RC Plus and Changed it to the RC Pro OS. There is a caveat though. The seller emphasizes that some buttons don't work and the firmware cannot be upgraded.
Here is his quote: "
Important Note: The remote control you cannot upgrade controller firmware, otherwise it doesn't work. Thanks
Remote control button R1,R2,R3, C3 not working
Because this remote control is installed with DJI RC Pro system, not DJI RC PLUS system in controller, so you cannot update the firmware of the remote control, otherwise the remote control will not be able to be used and connected, it's very important, please note. Thank you "
Here is his quote: "
Important Note: The remote control you cannot upgrade controller firmware, otherwise it doesn't work. Thanks
Remote control button R1,R2,R3, C3 not working
Because this remote control is installed with DJI RC Pro system, not DJI RC PLUS system in controller, so you cannot update the firmware of the remote control, otherwise the remote control will not be able to be used and connected, it's very important, please note. Thank you "