The 3D printer market isn't based on selling $20 cables for $3k based on some bullshit pseudo-science marketing.
https://www.audiodesign.co.uk/index.html
I'm guessing he expected to see Mark fail to repair it, and instead talk about how amazing and advanced his product is.
Far lower than that. Most EEGs at the scalp are in the 10-100 µV range.