The best one I have found yet was in a catelogue (sorry I don't remember
which one, but maybe someone on the FML will recognize the product).  It had
a plastic kind of snap in clasp.  Kind of like a seat belt buckle in that
you push the two pieces together and it snaps shut and when you want to take
it off, you push in (there is center cut out where you can push in the piece
that is inside).  Velcro never seemed to hold and the regular metal pin
buckles either come off or take to long to figure out the right setting.
With the plastic one, you adjust the size first and then just snap on and
off.  The size stays the same since it has nothing to do with the device
that closes it.  Good luck finding it.
 
  Rebecca, M&J
[Posted in FML issue 1838]