A:Answer I somehow missed that this is for Landline phones. This is NOT for cell phones, which I read on the box when it arrived but missed in the item description.
It does not fit cell phones, the jack is different size than for any earbuds etc normally used with cell. I ordered an adapter to go from the 2.5mm or 3.5mm whatever it is, to be able to use it for Galaxy 8.
I feel that people still make comments about the quality of my calls after a few weeks, so I just ordered a bluetooth headset instead.