You can find that out by compairing what Peter Gamma from www.petergamma.org has written unter PiEEG: https://petergamma.org/tag/pi-eeg/ And compare it to what he has written over OpenBCI: https://petergamma.org/tag/openbci/ PiEEG started selling in November 2023 and then was pulled from the market again at the beginning of 2024, after Peter Gamma from www.petergamma.org had critizised PiEEG. …