The pins in the socket itself are on a 4x4mm pitch, the two rows of pins that go to a circuit board seem to be intended to be 3mm apart.
The spring clips seem to need a 4mm hole. The centre line between the two clips seems to be 10mm from the centre of the nearest row of pins, and the clips themselves seem to be 20mm centre to centre.
Reverse-engineering stuff made to metric measurements is so much more pleasing than those made in old money. Japanese hardware just hits different.



















































