The MicroSD card produced by regular manufacturers should be used for the Xiaomi Smart Camera C500 Pro, preferably a dedicated card for security surveillance.
The maximum supported capacity of a MicroSD card is 256GB (256GB, exFAT format MicroSD card needs to be formatted into FAT32 format in [Settings] >> [Storage settings] by going to the Camera page in the Mi Home/Xiaomi Home APP), and it is recommended that the read/write speed of the card is not lower than class U1/Class 10.
For your reference, here is some information about the storage time of the Xiaomi Smart Camera C500 Pro:
1. The 256GB memory card is expected to store videos for about 20 days;
2. The 128GB memory card is expected to store videos for about 10 days;
3. The 64GB memory card is expected to store videos for about 5 days;
4. The 32GB memory card is expected to store videos for about 3 days;
5. The 16GB memory card is expected to store videos for about 1 day.
Note:
The resolution of the video recorded into the memory card is 2960 x 1666.