On Wed, 25 Nov 2015 10:30:48 -0500, "Ralph Mowery"
wrote:

I noticed that instead of the old paper or plastic keepers on the duplex
recepticals now one end has a brass or copper item to keep the screw with it
on one end.

What is the reson for that ?


That is a "self grounding" receptacle and could legally be installed
in a grounded metal box without using the ground wire terminal on the
device. It is still a good idea to use the wire tho.
These are handy if you are retrofitting a 3 prong receptacle in a box
that was grounded but still only had the 2 prong devices installed.
(somewhat common for a while in the 50s)