I have one. Works great with my Tello and better with a WiFi extender. Downloaded AltLimitTELLO and went 90’ high, on a calm day. Right above me. It will go far out horizontally also, maybe too far haha. I emailed Gamesir and they confirmed it’s only for the Tello. Which I think is ridiculous. On iPhone 8 Plus BTW. Gamesir’s response
Thank you for purchase at GameSir!
It's not usable as a standard bluetooth gaming controller ，And it can only be used with a Tello.
OK, I talked to the developer and there are no ads. He also confirmed the max height is 30m. You only have to run the app whenever there is a firmware update.
So I went ahead and tried it and it worked perfectly. I will say that once you get over 20m, the wind becomes increasingly a bigger problem for this little drone. Even with just a slight wind, all pictures were at a 10% to 15% angle. However, I was able to get all the way up to 30m, so it definitely works.