It appears to me that most all microSD cards should work fine since they can all write much more the a mere 10MB/sec. I have never noticed any difference with the DJI cards versus the other 32GB and 64GB cards that I've bought from Samsung and SanDisk. They all work just fine. The H.264 compression in the bird camera is designed to run at a certain max speed, and I'm sure the chip DJI selected for that is well defined in the chip manufacturers datasheet at 60Mb/sec (7.5MB/sec), so there's no interpretation or fudge room. This speed is also typical for point and shoot cameras, likely due to similar compression chips in this price range. As others have mentioned, if you're using a more expensive Nikon or Canon camera that can write much faster, the speed of the flash may be more important to an extent that you would see difference in the resulting playback of video. However, I don't see flash speed as an issue with P3 or P4 cameras, every UHS1 Class 10 micro SD I've bought at Costco or Amazon works great. I happen to prefer 32GB size, enough for 5 to 6 flights (1080@60fps). They only cost $10/ea. IMO, 64GB is too big, holding too much video that would be bad if something happened to the one chip. I like keeping my videos spread out over multiple chips for less risk.