Hans device fitment question

[ghassler]

I just bought a new Hans device in the medium size.  My neck measures about 16" (if I'm measuring right) which is near the middle of what the medium is supposed to fit and on the low side of the large size.

With that said, the device seems small.  I wouldn't say it's completely uncomfortable, but it's definitely smaller that I thought.  How should a Hans device fit on your neck and shoulders?  Can you fit the device over your head to put it on or do you have to slide it on from the back?