I'm having a hard time reconciling your text with your picture.
Looks more like 1cm cubes?
And the contact is the circular spot on the bottom of the key?
Rather large???
What part got removed by the customer?






Sorry, that's a typo, that should be 10mm x 10mm x 10mm cubes, as the ruler
in the photo shows.
That same photo with the ruler shows the round pad to be about 5mm diameter,
much larger than the key contact strips and button pads I find on
contemporary equipment.
This is old school manufacturing.




Gareth.