Interesting. But note:
- they are listed under "collectables - ethnographic" and not offered as tools, even if the company name has the word 'tools' in it.
- the other makers of holdfasts all make them around 19mm not 10
- they are very cheap.
I reckon they are only meant to look the part, from a distance, not for doing actual woodwork.
Making 'faithfull copies of historic tools' is fraught with difficulty when going this far back. The number of actual tools surviving is tiny so most of the evidence is from pictures, where often the illustrator did not really understand what he was drawing, so simplifications and errors arise.
If you want a good tool to hold wood on your bench, I suggest you look at Workshop Heaven - as recently discussed on here.