Question about SanDisk Extreme Pro

Hi, as Pagasign has already explained, firstly there is the format (SDXC vs microSDXC with SD adapter) and the capacity (128Gb vs 400Gb). Then, another main difference between the two memory cards are the read (300 MB/s vs. 200 MB/s) and write (260 MB/s vs. 140 MB/s) speeds. This memory card is UHS-II compliant (backwards compatible with UHS-I) and the other only UHS-I compliant (which supports lower data transfer speeds).

If the purpose of the drone is to record 4K video, the memory card must support a minimum continuous write speed of at least 30MB/s. The cheapest memory card is more than sufficient for this.

This memory card is more for photographers whose camera supports UHS-II (putting a UHS-II card in a camera that only supports UHS-I is a waste of money as the memory card will not be used to its full potential) and who need to record 4K video. (putting a UHS-II card in a UHS-I compatible camera is a waste of money as the memory card will not be used to its full potential) and who need a high write rate to save the pictures from the camera buffer to the memory card as quickly as possible (very important in burst mode to avoid saturating the camera buffer).

There are several differences. The most important: the above is a large SD card. It probably won't fit in a drone. The MicroSDXC you mentioned is a small MicroSD card. I don't need to explain the other differences. 99.9% of the time your son will need a MicroSDXC card for the drone. You're well advised to go with the 400GB version from SanDisk.