So this is just a quick one, or two. None of this is advertised by either SanDisk (they only say their card readers are supported) or ProGrade Digital (I don’t see any mention of non-standard SanDisk speeds on their site), so your milege may vary.

1. If you use SanDisk UHS-I SD cards advertised for 170 MB/s in a SanDisk reader, based on my testing ProGrade Digital’s CFExpress + UHS-II SD reader is also capable of reading these cards at 170 MB/s speed.
2. Apparently many SanDisk cards advertised with only 95 MB/s read speeds, can also be read at 170 MB/s. All of my 64 GB and 128 GB Extreme Pro UHS-I SD cards, even though they’re advertised at 95 MB/s can be read in the above reader at 170 MB/s. Though the caveat is that they’re fairly new cards too.