HI Veg.
I think the older tags had wiring in the lids the black round one was, pushed against by the the tube inside the agitator to start agitation, what we all know as a filter inside a tag agitator was at that time a solid piece of metal used as a float to push up and signal a full tub of water. the one below it was an off balance switch, if unbalance occured the agitator would strike this switch and stop the spin. Now i hope im right, but I picked this up in discussion in this site. alr2903. Something new here everyday LOL>