ZX81 Mechanical Keyboard
That is a sweet keyboard.It is rather better than my homemade one from 1982https://twitter.com/njcw/status/1368566103933337603My dad gave me a old keyboard from something and I traced the zx81 PCB to discover how it was wired, then rewired the new keyboard the same.I connected it by burning a hole in the case with my soldering iron to poke the wires through!It was a dream compared to the membrane keyboard.