does not specify uncompressed and compressed diameters of the male ‘pin’ - so what is it?
We do not have a manufacturer specification for the compressed and uncompressed dimensions of the male header pins. I used my caliper to measure the dimensions of a very small subset of the jumper wires we have and this is what I found:
The uncompressed male pins were roughly a 25 mil square.
To test the compressed size, I closed my caliper as tightly as I could with my thumb. With more force, the compression will probably be more. The male pins are a U shape so their compressed size is not the same in both directions. In one direction, the compressed size varied from 24 mil to 25 mil. In the other direction, the compressed size varied from 23.5 to 24.5 mil.
More generally, these header pins are designed to work with breadboards, 0.1" female header pins, and any female receptacle designed to take a 25 mil square male pin.
Please let me know if you have addition questions about the dimensions of the header pins or my measurement process.